Showing posts with label mining. Show all posts
Showing posts with label mining. Show all posts

Monday, September 21, 2020

Veins of the Earth

 

Antonio Neri, "The Mineral Gold"
Neri 1598-1600 (Ferguson 67), f. 5r.
Over a decade before Antonio Neri wrote L’Arte Vetraria, the book on glassmaking for which he would become famous, he wrote an illustrated manuscript on the subject of alchemy. Begun around 1598 and completed in 1600, this is Neri's earliest known work, written very shortly after he was ordained as a Catholic priest. 

The illustrations are divided between technical depictions of chemical apparatus and allegorical images meant to show philosophical relationships within the natural world. Two of Neri's pictures from this latter group, respectively, show veins of gold and silver growing in the earth. The veins are depicted exactly like the arteries of an animal. In both pictures, they radiate out around fiery holes in the ground, what one might presume to be volcanos. Overhead the sun shines down on the gold and the moon over the silver. Further up in the sky, Neri shows the constellations associated with each metal; Leo the lion for gold and Cancer the crab for silver (his rendition looking more like a lobster).

It was no flight of fancy that mined metal and ore deposits were depicted as literal veins. It was widely thought these were living structures, which carried the earth’s nutrients. In one of Neri's final works, his 1613 manuscript Discorso, he explains the ancient theory that gold could occur as immature seed material, left over from the primordial creation. If properly nourished, this seed would mature and grow into the precious metal, and with the appropriate knowledge this natural process could be restarted, or accelerated and the gold could be brought to perfection by artificial means. 

Antonio Neri, "The Mineral Silver"
Neri 1598-1600 (Ferguson 67), f. 6r.
The idea that mined mineral deposits could regenerate naturally, if left to rest, is an ancient concept, one that persisted long past Neri’s era. In 1814, writing about tin mining in "On the Veins of Cornwall," William Phillips complained to the Geological Society of London, that armed with some current scientific knowledge, "nor would many miners […] believe, even to this day, in the regeneration of metals." Phillips quoted from an 1811 survey by
Tonkin, in Carew's survey of Cornwall: "Whether tin doth grow again, and fill up places which have been formerly wrought away, or whether it only seperateth itself from the consumed offal, hath been much controverted, and is not to this day decided." And  "whether—dead lodes—that have not one grain of tin in them—may not hereafter be impregnated,  matured,  and prove a future supply to the country, when the present lodes are exhausted, I think well deserves our highest consideration."  

At base, this is not superstition nor wild speculation, but rather considered judgments of thoughtful men making careful observations. Mines were often attended by acidic or other caustic liquids, either produced naturally or by washing operations, which leached out and dissolved various solubles. These liquids could sometimes dissolve metal out of ore and redeposit it elsewhere. Abandoned mines, it was noticed, could exhibit new crystal growth after a period of years or centuries. Today, the redeposition of minerals is a well accepted phenomenon, however, where it does occur it takes place not on a human time scale, but on a geological one, over millions of years.

*This post first appeared here in a slightly different form on 2 December 2013.

Friday, July 17, 2020

Primordial Matter

16th century Mining practices, 
from Agricola, De Re Metallica
In the early seventeenth century, Florentine priest Antonio Neri wrote the first printed book devoted to formulating glass from raw materials. His work is called L'Arte Vetraria, which translates to "the art of glassmaking." The book became quite famous and this is what he is remembered for today, yet he considered himself first and foremost an alchemist. In previous posts, we have explored the commonalities between glassmaking, medicine and the apothecary's trade. Another field closely connected to alchemy was mining. 

In the seventeenth century, the earth was considered a living entity; metals were found to occur in "veins" which were thought to grow and once mined, regenerated over time. The metals themselves were thought to undergo a maturation process. The thinking was that primordial material left over from the creation of the world exerted its influence deep in the ground. Nurtured by the earth, under the influence of the suns rays, a process took place that eventually turned base metals into the more noble silver and gold. As far as Neri was concerned, alchemy was the art of imitating and enhancing natural processes that were already at work. In his manuscript Discorso, he writes:
I feel that the more perfect the art the most simple it is; so the authors [of alchemy] most unanimously agree that the ‘primordial material’ [prima materia] of the [philosopher’s] stone is something vile [base] and not bought with money, but easy to find. Moreover, the manner of work must imitate nature, which in order to produce gold makes use of the singular or simple material, which is the seed of gold, of a single vessel, which is the ‘womb of the earth’ [seno della terra] and of a single natural and vital fire, which is the sun.*
Elsewhere in the manuscript, Neri discusses several specific mines. He discusses the use of "vitriol" water that flowed in certain mines and how it could be used to transmute iron into copper. He discusses an unidentified mine "some distance from Leiden" (possibly in Limburg) and another in Slovakia in the town of Smolnik. It is reasonable to think that Neri visited these places himself. A third location, which he purposely keeps under wraps, is where he obtained "immature" gold that he was able to "multiply" through alchemical manipulation. With a certain disappointment, he writes "To this day I have never found another mine like it, and therefore suitable for this purpose." Clearly, he spent a significant portion of his time looking. He advises:
The gold mines are not all in the same condition, which is well understood for those of silver and all the other [metals]. Some are already perfect, in which nature has done what it could do and reduced the gold to its maturity, while other [mines] are still imperfect and in their infancy*
In his work for Medici prince Don Antonio in Florence, Neri's assistant/disciple was Agnolo della Casa. Della Casa took copious notes of Neri's experiments, and literally filled thousands of pages in notebooks that are today held by the National Library in Florence. Much of this material dealt with the transmutation of metals, and as we have seen Neri was not only concerned with materials, but with their specific place of origin. His first manuscript was titled "Treasure of the World, By Priest Antonio Neri – which [covers] the whole of alchemy with various illustrations, not only of the furnaces, vessels and chemical instruments but with other illustrations concerning the mining of all the metals." For he and his colleagues, mining and alchemy shared theoretical connections but also familial ones. Della Casa had a relative named Filippo Talducci della Casa (1543- c.1615), who was a celebrated alchemist and mining engineer, working in Prague and Krakow for the Holy Roman Emperor. Last but not least, there was also a practical connection. Mining provided many of the raw materials used in Antonio Neri’s glassmaking activities.  

* For a full discussion of Neri’s Discorso, see M. G. Grazzini, “Discorso sopra la Chimica: The Paracelsian Philosophy of Antonio Neri”, Nuncius 27, pp. 411-467.

** This post first appeared here 30 April 2014.

Wednesday, July 8, 2020

Zaffer

Antique Apothecary jars,
cobalt blue glass.
As best as I can remember, the first time that I really noticed glass was at four or five years old, at my grandmother's house in Queens, New York. The sunlight filtering through a low window caught my eye with a brilliant blue glint through a small cobalt glass bottle.  My grandmother held it up to the light for me and I was enchanted; transported into a realm of exquisite pure color.

Little did I know that the spell cast on me at such a young age had been cast on Egyptian pharaohs of the eighteenth dynasty and on Persian princesses, two thousands years ago, by their cobalt glass jewelry. In all three cases, the deep rich blue of cobalt oxide glass was responsible. Today, the source of ancient Middle Eastern cobalt is unknown, possibly West Africa, but more recently, in the Renaissance; it was mined in Hungary, in Bohemia and in German Saxony, where it was called "zaffer," after its sapphire color.

Legend tells that sixteenth century silver miners in Germany amassed a hoard of smaltite thinking it was silver ore. When they tried to smelt it, the arsenic which cobalt ores always have, evolved highly toxic fumes that made them sick. Discouraged and maligned, they said the product of their labors was cursed by goblins; they named it "kobald" (cobalt) after the evil spirits. The theme of 'evil spirits' (toxic fumes) was common in mining circles. A mythology persisted from ancient times up until the eighteenth century that divided the spirits into two groups; mischievous, and malevolent. The mischievous spirits played tricks on the miner's perception and equipment, the malevolent spirits could stop a man dead in his tracks, literally. 

Regardless of the difficulties both terestrial and otherwise, a strong market developed for the newly found "kobald" among artists for paint, potters for glazes, and glassmakers. The Saxon miners gained a reputation for producing the finest zaffer.

In his glassmaking book L'Arte Vetraria, Antonio Neri describes his method for purifying and preparing zaffer for use in glass. It is a recipe that would stand the test of time, still quoted by authors into the nineteenth and twentieth century.

To Prepare Zaffer, Which Serves for Many Colors in the Art of Glassmaking

You should get zaffer in large pieces and put it in earthenware oven-pans holding it in the furnace chamber for half a day. Then put it into iron ladles to inflame it in the furnace. Heat it well, then take and sprinkle it with strong vinegar. When cold, grind it finely over a porphyry stone into glazed earthen pots with hot water. Then wash more water over it always leaving the zaffer to settle in the bottom.

Now gently decant, to carry away the sediment and impurities of the zaffer. The good part and pigment of the zaffer will remain in the bottom. The pigment remains are now prepared and purified to be far better than it was at first, which will make clear and limpid pigment. This zaffer should be dried and kept in sealed vessels for use, which will be much improved over the original.


Until the mid 1700s zaffer had been associated with silver and copper mines, and was commonly thought to be a derivative of copper. It was Swedish chemist Georg Brandt who finally isolated the new metal, and gave it the name which honors the miners and the subterranean spirits which still can cast a spell on us through its deep pure blue color in glass.

* This post first appeared here in a slightly different form on 4 April 2014.

Monday, February 3, 2020

Veins of the Earth

Antonio Neri, "The Mineral Gold"
Neri 1598-1600 (Ferguson 67), f. 5r.
Over a decade before Antonio Neri wrote L’Arte Vetraria, the book on glassmaking for which he would become famous, he wrote an illustrated manuscript on the subject of alchemy. Begun around 1598 and completed in 1600, this is Neri's earliest known work, written very shortly after he was ordained as a Catholic priest. 

The illustrations are divided between technical depictions of chemical apparatus and allegorical images meant to show philosophical relationships within the natural world. Two of Neri's pictures from this latter group, respectively, show veins of gold and silver growing in the earth. The veins are depicted exactly like the arteries of an animal. In both pictures, they radiate out around fiery holes in the ground, what one might presume to be volcanos. Overhead the sun shines down on the gold and the moon over the silver. Further up in the sky, Neri shows the constellations associated with each metal; Leo the lion for gold and Cancer the crab for silver (his rendition looking more like a lobster).

It was no flight of fancy that mined metal and ore deposits were depicted as literal veins. It was widely thought these were living structures, which carried the earth’s nutrients. In one of Neri's final works, his 1613 manuscript Discorso, he explains the ancient theory that gold could occur as immature seed material, left over from the primordial creation. If properly nourished, this seed would mature and grow into the precious metal, and with the appropriate knowledge this natural process could be restarted, or accelerated and the gold could be brought to perfection by artificial means. 

Antonio Neri, "The Mineral Silver"
Neri 1598-1600 (Ferguson 67), f. 6r.
The idea that mined mineral deposits could regenerate naturally, if left to rest, is an ancient concept, one that persisted long past Neri’s era. In 1814, writing about tin mining in "On the Veins of Cornwall," William Phillips complained to the Geological Society of London, that armed with some current scientific knowledge, "nor would many miners […] believe, even to this day, in the regeneration of metals." Phillips quoted from an 1811 survey by
Tonkin, in Carew's survey of Cornwall: "Whether tin doth grow again, and fill up places which have been formerly wrought away, or whether it only seperateth itself from the consumed offal, hath been much controverted, and is not to this day decided." And  "whether—dead lodes—that have not one grain of tin in them—may not hereafter be impregnated,  matured,  and prove a future supply to the country, when the present lodes are exhausted, I think well deserves our highest consideration."  

At base, this is not superstition nor wild speculation, but rather considered judgments of thoughtful men making careful observations. Mines were often attended by acidic or other caustic liquids, either produced naturally or by washing operations, which leached out and dissolved various solubles. These liquids could sometimes dissolve metal out of ore and redeposit it elsewhere. Abandoned mines, it was noticed, could exhibit new crystal growth after a period of years or centuries. Today, the redeposition of minerals is a well accepted phenomenon, however, where it does occur it takes place not on a human time scale, but on a geological one, over millions of years.

*This post first appeared here in a slightly different form on 2 December 2013.

Wednesday, September 11, 2019

Zaffer

Antique Apothecary jars,
cobalt blue glass.
As best as I can remember, the first time that I really noticed glass was at four or five years old, at my grandmother's house in Queens, New York. The sunlight filtering through a low window caught my eye with a brilliant blue glint through a small cobalt glass bottle.  My grandmother held it up to the light for me and I was enchanted; transported into a realm of exquisite pure color.

Little did I know that the spell cast on me at such a young age had been cast on Egyptian pharaohs of the eighteenth dynasty and on Persian princesses, two thousands years ago, by their cobalt glass jewelry. In all three cases, the deep rich blue of cobalt oxide glass was responsible. Today, the source of ancient Middle Eastern cobalt is unknown, possibly West Africa, but more recently, in the Renaissance; it was mined in Hungary, in Bohemia and in German Saxony, where it was called "zaffer," after its sapphire color.

Legend tells that sixteenth century silver miners in Germany amassed a hoard of smaltite thinking it was silver ore. When they tried to smelt it, the arsenic which cobalt ores always have, evolved highly toxic fumes that made them sick. Discouraged and maligned, they said the product of their labors was cursed by goblins; they named it "kobald" (cobalt) after the evil spirits. The theme of 'evil spirits' (toxic fumes) was common in mining circles. A mythology persisted from ancient times up until the eighteenth century that divided the spirits into two groups; mischievous, and malevolent. The mischievous spirits played tricks on the miner's perception and equipment, the malevolent spirits could stop a man dead in his tracks, literally. 

Regardless of the difficulties both terestrial and otherwise, a strong market developed for the newly found "kobald" among artists for paint, potters for glazes, and glassmakers. The Saxon miners gained a reputation for producing the finest zaffer.

In his glassmaking book L'Arte Vetraria, Antonio Neri describes his method for purifying and preparing zaffer for use in glass. It is a recipe that would stand the test of time, still quoted by authors into the nineteenth and twentieth century.

To Prepare Zaffer, Which Serves for Many Colors in the Art of Glassmaking

You should get zaffer in large pieces and put it in earthenware oven-pans holding it in the furnace chamber for half a day. Then put it into iron ladles to inflame it in the furnace. Heat it well, then take and sprinkle it with strong vinegar. When cold, grind it finely over a porphyry stone into glazed earthen pots with hot water. Then wash more water over it always leaving the zaffer to settle in the bottom.

Now gently decant, to carry away the sediment and impurities of the zaffer. The good part and pigment of the zaffer will remain in the bottom. The pigment remains are now prepared and purified to be far better than it was at first, which will make clear and limpid pigment. This zaffer should be dried and kept in sealed vessels for use, which will be much improved over the original.


Until the mid 1700s zaffer had been associated with silver and copper mines, and was commonly thought to be a derivative of copper. It was Swedish chemist Georg Brandt who finally isolated the new metal, and gave it the name which honors the miners and the subterranean spirits which still can cast a spell on us through its deep pure blue color in glass.

* This post first appeared here in a slightly different form on 4 April 2014.

Friday, September 6, 2019

Primordial Matter

16th century Mining practices, 
from Agricola, De Re Metallica
In the early seventeenth century, Florentine priest Antonio Neri wrote the first printed book devoted to formulating glass from raw materials. His work is called L'Arte Vetraria, which translates to "the art of glassmaking." The book became quite famous and this is what he is remembered for today, yet he considered himself first and foremost an alchemist. In previous posts, we have explored the commonalities between glassmaking, medicine and the apothecary's trade. Another field closely connected to alchemy was mining. 

In the seventeenth century, the earth was considered a living entity; metals were found to occur in "veins" which were thought to grow and once mined, regenerate over time. The metals themselves were thought to undergo a maturation process. Primordial material left over from the creation of the world exerted its influence deep in the ground. Nurtured by the earth, under the influence of the suns rays, a process took place that eventually turned base metals into the more noble silver and gold. As far as Neri was concerned, alchemy was the art of imitating and enhancing natural processes that were already at work. In his manuscript Discorso, he writes:
I feel that the more perfect the art the most simple it is; so the authors [of alchemy] most unanimously agree that the ‘primordial material’ [prima materia] of the [philosopher’s] stone is something vile [base] and not bought with money, but easy to find. Moreover, the manner of work must imitate nature, which in order to produce gold makes use of the singular or simple material, which is the seed of gold, of a single vessel, which is the ‘womb of the earth’ [seno della terra] and of a single natural and vital fire, which is the sun.*
Elsewhere in the manuscript, Neri discusses several specific mines. He discusses the use of "vitriol" water that flowed in certain mines and how it could be used to transmute iron into copper. He discusses an unidentified mine "some distance from Leiden" (possibly in Limburg) and another in Slovakia in the town of Smolnik. It is reasonable to think that Neri visited these places himself. A third location, which he purposely keeps under wraps, is where he obtained "immature" gold that he was able to "multiply" through alchemical manipulation. With a certain disappointment, he writes "To this day I have never found another mine like it, and therefore suitable for this purpose." Clearly, he spent a significant portion of his time looking. He advises:
The gold mines are not all in the same condition, which is well understood for those of silver and all the other [metals]. Some are already perfect, in which nature has done what it could do and reduced the gold to its maturity, while other [mines] are still imperfect and in their infancy*
In his work for Medici prince Don Antonio in Florence, Neri's assistant/disciple was Agnolo della Casa. Della Casa took copious notes of Neri's experiments, and literally filled thousands of pages in notebooks that are today held by the National Library in Florence. Much of this material dealt with the transmutation of metals, and as we have seen Neri was not only concerned with materials, but with their specific place of origin. His first manuscript was titled "Treasure of the World, By Priest Antonio Neri – which [covers] the whole of alchemy with various illustrations, not only of the furnaces, vessels and chemical instruments but with other illustrations concerning the mining of all the metals." For he and his colleagues, mining and alchemy shared theoretical connections but also familial ones. Della Casa had a relative named Filippo Talducci della Casa (1543- c.1615), who was a celebrated alchemist and mining engineer, working in Prague and Krakow for the Holy Roman Emperor. Last but not least, there was also a practical connection. Mining provided many of the raw materials used in Antonio Neri’s glassmaking activities.  

* For a full discussion of Neri’s Discorso, see M. G. Grazzini, “Discorso sopra la Chimica: The Paracelsian Philosophy of Antonio Neri”, Nuncius 27, pp. 411-467.

** This post first appeared here 30 April 2014.

Monday, July 1, 2019

Veins of the Earth

Antonio Neri, "The Mineral Gold"
Neri 1598-1600 (Ferguson 67), f. 5r.
Over a decade before Antonio Neri wrote L’Arte Vetraria, the book on glassmaking for which he would become famous, he wrote an illustrated manuscript on the subject of alchemy. Begun around 1598 and completed in 1600, this is Neri's earliest known work, written very shortly after he was ordained as a Catholic priest. 

The illustrations are divided between technical depictions of chemical apparatus and allegorical images meant to show philosophical relationships within the natural world. Two of Neri's pictures from this latter group, respectively, show veins of gold and silver growing in the earth. The veins are depicted exactly like the arteries of an animal. In both pictures, they radiate out around fiery holes in the ground, what one might presume to be volcanos. Overhead the sun shines down on the gold and the moon over the silver. Further up in the sky, Neri shows the constellations associated with each metal; Leo the lion for gold and Cancer the crab for silver (his rendition looking more like a lobster).

It was no flight of fancy that mined metal and ore deposits were depicted as literal veins. It was widely thought these were living structures, which carried the earth’s nutrients. In one of Neri's final works, his 1613 manuscript Discorso, he explains the ancient theory that gold could occur as immature seed material, left over from the primordial creation. If properly nourished, this seed would mature and grow into the precious metal, and with the appropriate knowledge this natural process could be restarted, or accelerated and the gold could be brought to perfection by artificial means. 

Antonio Neri, "The Mineral Silver"
Neri 1598-1600 (Ferguson 67), f. 6r.
The idea that mined mineral deposits could regenerate naturally, if left to rest, is an ancient concept, one that persisted long past Neri’s era. In 1814, writing about tin mining in "On the Veins of Cornwall," William Phillips complained to the Geological Society of London, that armed with some current scientific knowledge, "nor would many miners […] believe, even to this day, in the regeneration of metals." Phillips quoted from an 1811 survey by
Tonkin, in Carew's survey of Cornwall: "Whether tin doth grow again, and fill up places which have been formerly wrought away, or whether it only seperateth itself from the consumed offal, hath been much controverted, and is not to this day decided." And  "whether—dead lodes—that have not one grain of tin in them—may not hereafter be impregnated,  matured,  and prove a future supply to the country, when the present lodes are exhausted, I think well deserves our highest consideration."  

At base, this is not superstition nor wild speculation, but rather considered judgments of thoughtful men making careful observations. Mines were often attended by acidic or other caustic liquids, either produced naturally or by washing operations, which leached out and dissolved various solubles. These liquids could sometimes dissolve metal out of ore and redeposit it elsewhere. Abandoned mines, it was noticed, could exhibit new crystal growth after a period of years or centuries. Today, the redeposition of minerals is a well accepted phenomenon, however, where it does occur it takes place not on a human time scale, but on a geological one, over millions of years.

*This post first appeared here in a slightly different form on 2 December 2013.

Wednesday, January 2, 2019

Zaffer

Antique Apothecary jars,
cobalt blue glass.
As best as I can remember, the first time that I really noticed glass was at four or five years old, at my grandmother's house in Queens, New York. The sunlight filtering through a low window caught my eye with a brilliant blue glint through a small cobalt glass bottle.  My grandmother held it up to the light for me and I was enchanted; transported into a realm of exquisite pure color.

Little did I know that the spell cast on me at such a young age had been cast on Egyptian pharaohs of the eighteenth dynasty and on Persian princesses, two thousands years ago, by their cobalt glass jewelry. In all three cases, the deep rich blue of cobalt oxide glass was responsible. Today, the source of ancient Middle Eastern cobalt is unknown, possibly West Africa, but more recently, in the Renaissance; it was mined in Hungary, in Bohemia and in German Saxony, where it was called "zaffer," after its sapphire color.

Legend tells that sixteenth century silver miners in Germany amassed a hoard of smaltite thinking it was silver ore. When they tried to smelt it, the arsenic which cobalt ores always have, evolved highly toxic fumes that made them sick. Discouraged and maligned, they said the product of their labors was cursed by goblins; they named it "kobald" (cobalt) after the evil spirits. The theme of 'evil spirits' (toxic fumes) was common in mining circles. A mythology persisted from ancient times up until the eighteenth century that divided the spirits into two groups; mischievous, and malevolent. The mischievous spirits played tricks on the miner's perception and equipment, the malevolent spirits could stop a man dead in his tracks, literally. 

Regardless of the difficulties both terestrial and otherwise, a strong market developed for the newly found "kobald" among artists for paint, potters for glazes, and glassmakers. The Saxon miners gained a reputation for producing the finest zaffer.

In his glassmaking book L'Arte Vetraria, Antonio Neri describes his method for purifying and preparing zaffer for use in glass. It is a recipe that would stand the test of time, still quoted by authors into the nineteenth and twentieth century.

To Prepare Zaffer, Which Serves for Many Colors in the Art of Glassmaking

You should get zaffer in large pieces and put it in earthenware oven-pans holding it in the furnace chamber for half a day. Then put it into iron ladles to inflame it in the furnace. Heat it well, then take and sprinkle it with strong vinegar. When cold, grind it finely over a porphyry stone into glazed earthen pots with hot water. Then wash more water over it always leaving the zaffer to settle in the bottom.

Now gently decant, to carry away the sediment and impurities of the zaffer. The good part and pigment of the zaffer will remain in the bottom. The pigment remains are now prepared and purified to be far better than it was at first, which will make clear and limpid pigment. This zaffer should be dried and kept in sealed vessels for use, which will be much improved over the original.


Until the mid 1700s zaffer had been associated with silver and copper mines, and was commonly thought to be a derivative of copper. It was Swedish chemist Georg Brandt who finally isolated the new metal, and gave it the name which honors the miners and the subterranean spirits which still can cast a spell on us through its deep pure blue color in glass.

* This post first appeared here in a slightly different form on 4 April 2014.

Friday, December 28, 2018

Primordial Matter

16th century Mining practices, 
from Agricola, De Re Metallica
In the early seventeenth century, Florentine priest Antonio Neri wrote the first printed book devoted to formulating glass from raw materials. His work is called L'Arte Vetraria, which translates to "the art of glassmaking." The book became quite famous and this is what he is remembered for today, yet he considered himself first and foremost an alchemist. In previous posts, we have explored the commonalities between glassmaking, medicine and the apothecary's trade. Another field closely connected to alchemy was mining. 

In the seventeenth century, the earth was considered a living entity; metals were found to occur in "veins" which were thought to grow and once mined, regenerate over time. The metals themselves were thought to undergo a maturation process. Primordial material left over from the creation of the world exerted its influence deep in the ground. Nurtured by the earth, under the influence of the suns rays, a process took place that eventually turned base metals into the more noble silver and gold. As far as Neri was concerned, alchemy was the art of imitating and enhancing natural processes that were already at work. In his manuscript Discorso, he writes:
I feel that the more perfect the art the most simple it is; so the authors [of alchemy] most unanimously agree that the ‘primordial material’ [prima materia] of the [philosopher’s] stone is something vile [base] and not bought with money, but easy to find. Moreover, the manner of work must imitate nature, which in order to produce gold makes use of the singular or simple material, which is the seed of gold, of a single vessel, which is the ‘womb of the earth’ [seno della terra] and of a single natural and vital fire, which is the sun.*
Elsewhere in the manuscript, Neri discusses several specific mines. He discusses the use of "vitriol" water that flowed in certain mines and how it could be used to transmute iron into copper. He discusses an unidentified mine "some distance from Leiden" (possibly in Limburg) and another in Slovakia in the town of Smolnik. It is reasonable to think that Neri visited these places himself. A third location, which he purposely keeps under wraps, is where he obtained "immature" gold that he was able to "multiply" through alchemical manipulation. With a certain disappointment, he writes "To this day I have never found another mine like it, and therefore suitable for this purpose." Clearly, he spent a significant portion of his time looking. He advises:
The gold mines are not all in the same condition, which is well understood for those of silver and all the other [metals]. Some are already perfect, in which nature has done what it could do and reduced the gold to its maturity, while other [mines] are still imperfect and in their infancy*
In his work for Medici prince Don Antonio in Florence, Neri's assistant/disciple was Agnolo della Casa. Della Casa took copious notes of Neri's experiments, and literally filled thousands of pages in notebooks that are today held by the National Library in Florence. Much of this material dealt with the transmutation of metals, and as we have seen Neri was not only concerned with materials, but with their specific place of origin. His first manuscript was titled "Treasure of the World, By Priest Antonio Neri – which [covers] the whole of alchemy with various illustrations, not only of the furnaces, vessels and chemical instruments but with other illustrations concerning the mining of all the metals." For he and his colleagues, mining and alchemy shared theoretical connections but also familial ones. Della Casa had a relative named Filippo Talducci della Casa (1543- c.1615), who was a celebrated alchemist and mining engineer, working in Prague and Krakow for the Holy Roman Emperor. Last but not least, there was also a practical connection. Mining provided many of the raw materials used in Antonio Neri’s glassmaking activities.  

* For a full discussion of Neri’s Discorso, see M. G. Grazzini, “Discorso sopra la Chimica: The Paracelsian Philosophy of Antonio Neri”, Nuncius 27, pp. 411-467.

** This post first appeared here 30 April 2014.

Friday, September 21, 2018

Veins of the Earth

Antonio Neri, "The Mineral Gold"
Neri 1598-1600 (Ferguson 67), f. 5r.
Over a decade before Antonio Neri wrote L’Arte Vetraria, the book on glassmaking for which he would become famous, he wrote an illustrated manuscript on the subject of alchemy. Begun around 1598 and completed in 1600, this is Neri's earliest known work, written very shortly after he was ordained as a Catholic priest. 

The illustrations are divided between technical depictions of chemical apparatus and allegorical images meant to show philosophical relationships within the natural world. Two of Neri's pictures from this latter group, respectively, show veins of gold and silver growing in the earth. The veins are depicted exactly like the arteries of an animal. In both pictures, they radiate out around fiery holes in the ground, what one might presume to be volcanos. Overhead the sun shines down on the gold and the moon over the silver. Further up in the sky, Neri shows the constellations associated with each metal; Leo the lion for gold and Cancer the crab for silver (his rendition looking more like a lobster).

It was no flight of fancy that mined metal and ore deposits were depicted as literal veins. It was widely thought these were living structures, which carried the earth’s nutrients. In one of Neri's final works, his 1613 manuscript Discorso, he explains the ancient theory that gold could occur as immature seed material, left over from the primordial creation. If properly nourished, this seed would mature and grow into the precious metal, and with the appropriate knowledge this natural process could be restarted, or accelerated and the gold could be brought to perfection by artificial means. 

Antonio Neri, "The Mineral Silver"
Neri 1598-1600 (Ferguson 67), f. 6r.
The idea that mined mineral deposits could regenerate naturally, if left to rest, is an ancient concept, one that persisted long past Neri’s era. In 1814, writing about tin mining in "On the Veins of Cornwall," William Phillips complained to the Geological Society of London, that armed with some current scientific knowledge, "nor would many miners […] believe, even to this day, in the regeneration of metals." Phillips quoted from an 1811 survey by
Tonkin, in Carew's survey of Cornwall: "Whether tin doth grow again, and fill up places which have been formerly wrought away, or whether it only seperateth itself from the consumed offal, hath been much controverted, and is not to this day decided." And  "whether—dead lodes—that have not one grain of tin in them—may not hereafter be impregnated,  matured,  and prove a future supply to the country, when the present lodes are exhausted, I think well deserves our highest consideration."  

At base, this is not superstition nor wild speculation, but rather considered judgments of thoughtful men making careful observations. Mines were often attended by acidic or other caustic liquids, either produced naturally or by washing operations, which leached out and dissolved various solubles. These liquids could sometimes dissolve metal out of ore and redeposit it elsewhere. Abandoned mines, it was noticed, could exhibit new crystal growth after a period of years or centuries. Today, the redeposition of minerals is a well accepted phenomenon, however, where it does occur it takes place not on a human time scale, but on a geological one, over millions of years.

*This post first appeared here in a slightly different form on 2 December 2013.

Wednesday, April 4, 2018

Zaffer

Antique Apothecary jars,
cobalt blue glass.
As best as I can remember, the first time that I really noticed glass was at four or five years old, at my grandmother's house in Queens, New York. The sunlight filtering through a low window caught my eye with a brilliant blue glint through a small cobalt glass bottle.  My grandmother held it up to the light for me and I was enchanted; transported into a realm of exquisite pure color.

Little did I know that the spell cast on me at such a young age had been cast on Egyptian pharaohs of the eighteenth dynasty and on Persian princesses, two thousands years ago, by their cobalt glass jewelry. In all three cases, the deep rich blue of cobalt oxide glass was responsible. Today, the source of ancient Middle Eastern cobalt is unknown, possibly West Africa, but more recently, in the Renaissance; it was mined in Hungary, in Bohemia and in German Saxony, where it was called "zaffer," after its sapphire color.

Legend tells that sixteenth century silver miners in Germany amassed a hoard of smaltite thinking it was silver ore. When they tried to smelt it, the arsenic which cobalt ores always have, evolved highly toxic fumes that made them sick. Discouraged and maligned, they said the product of their labors was cursed by goblins; they named it "kobald" (cobalt) after the evil spirits. The theme of 'evil spirits' (toxic fumes) was common in mining circles. A mythology persisted from ancient times up until the eighteenth century that divided the spirits into two groups; mischievous, and malevolent. The mischievous spirits played tricks on the miner's perception and equipment, the malevolent spirits could stop a man dead in his tracks, literally. 

Regardless of the difficulties both terestrial and otherwise, a strong market developed for the newly found "kobald" among artists for paint, potters for glazes, and glassmakers. The Saxon miners gained a reputation for producing the finest zaffer.

In his glassmaking book L'Arte Vetraria, Antonio Neri describes his method for purifying and preparing zaffer for use in glass. It is a recipe that would stand the test of time, still quoted by authors into the nineteenth and twentieth century.

To Prepare Zaffer, Which Serves for Many Colors in the Art of Glassmaking

You should get zaffer in large pieces and put it in earthenware oven-pans holding it in the furnace chamber for half a day. Then put it into iron ladles to inflame it in the furnace. Heat it well, then take and sprinkle it with strong vinegar. When cold, grind it finely over a porphyry stone into glazed earthen pots with hot water. Then wash more water over it always leaving the zaffer to settle in the bottom.

Now gently decant, to carry away the sediment and impurities of the zaffer. The good part and pigment of the zaffer will remain in the bottom. The pigment remains are now prepared and purified to be far better than it was at first, which will make clear and limpid pigment. This zaffer should be dried and kept in sealed vessels for use, which will be much improved over the original.


Until the mid 1700s zaffer had been associated with silver and copper mines, and was commonly thought to be a derivative of copper. It was Swedish chemist Georg Brandt who finally isolated the new metal, and gave it the name which honors the miners and the subterranean spirits which still can cast a spell on us through its deep pure blue color in glass.

* This post first appeared here in a slightly different form on 4 April 2014.

Friday, February 23, 2018

Primordial Matter

16th century Mining practices, 
from Agricola, De Re Metallica
In the early seventeenth century, Florentine priest Antonio Neri wrote the first printed book devoted to formulating glass from raw materials. His work is called L'Arte Vetraria, which translates to "the art of glassmaking." The book became quite famous and this is what he is remembered for today, yet he considered himself first and foremost an alchemist. In previous posts, we have explored the commonalities between glassmaking, medicine and the apothecary's trade. Another field closely connected to alchemy was mining. 

In the seventeenth century, the earth was considered a living entity; metals were found to occur in "veins" which were thought to grow and once mined, regenerate over time. The metals themselves were thought to undergo a maturation process. Primordial material left over from the creation of the world exerted its influence deep in the ground. Nurtured by the earth, under the influence of the suns rays, a process took place that eventually turned base metals into the more noble silver and gold. As far as Neri was concerned, alchemy was the art of imitating and enhancing natural processes that were already at work. In his manuscript Discorso, he writes:
I feel that the more perfect the art the most simple it is; so the authors [of alchemy] most unanimously agree that the ‘primordial material’ [prima materia] of the [philosopher’s] stone is something vile [base] and not bought with money, but easy to find. Moreover, the manner of work must imitate nature, which in order to produce gold makes use of the singular or simple material, which is the seed of gold, of a single vessel, which is the ‘womb of the earth’ [seno della terra] and of a single natural and vital fire, which is the sun.*
Elsewhere in the manuscript, Neri discusses several specific mines. He discusses the use of "vitriol" water that flowed in certain mines and how it could be used to transmute iron into copper. He discusses an unidentified mine "some distance from Leiden" (possibly in Limburg) and another in Slovakia in the town of Smolnik. It is reasonable to think that Neri visited these places himself. A third location, which he purposely keeps under wraps, is where he obtained "immature" gold that he was able to "multiply" through alchemical manipulation. With a certain disappointment, he writes "To this day I have never found another mine like it, and therefore suitable for this purpose." Clearly, he spent a significant portion of his time looking. He advises:
The gold mines are not all in the same condition, which is well understood for those of silver and all the other [metals]. Some are already perfect, in which nature has done what it could do and reduced the gold to its maturity, while other [mines] are still imperfect and in their infancy*
In his work for Medici prince Don Antonio in Florence, Neri's assistant/disciple was Agnolo della Casa. Della Casa took copious notes of Neri's experiments, and literally filled thousands of pages in notebooks that are today held by the National Library in Florence. Much of this material dealt with the transmutation of metals, and as we have seen Neri was not only concerned with materials, but with their specific place of origin. His first manuscript was titled "Treasure of the World, By Priest Antonio Neri – which [covers] the whole of alchemy with various illustrations, not only of the furnaces, vessels and chemical instruments but with other illustrations concerning the mining of all the metals." For he and his colleagues, mining and alchemy shared theoretical connections but also familial ones. Della Casa had a relative named Filippo Talducci della Casa (1543- c.1615), who was a celebrated alchemist and mining engineer, working in Prague and Krakow for the Holy Roman Emperor. Last but not least, there was also a practical connection. Mining provided many of the raw materials used in Antonio Neri’s glassmaking activities.  

* For a full discussion of Neri’s Discorso, see M. G. Grazzini, “Discorso sopra la Chimica: The Paracelsian Philosophy of Antonio Neri”, Nuncius 27, pp. 411-467.

** This post first appeared here 30 April 2014.

Friday, November 3, 2017

Veins of the Earth

Antonio Neri, "The Mineral Gold"
Neri 1598-2000 (Ferguson 67), f. 5r.
Over a decade before Antonio Neri wrote L’Arte Vetraria, the book on glassmaking for which he would become famous, he wrote an illustrated manuscript on the subject of alchemy. Begun around 1598 and completed in 1600, this is Neri's earliest known work, written very shortly after he was ordained as a Catholic priest. 

The illustrations are divided between technical depictions of chemical apparatus and allegorical images meant to show philosophical relationships within the natural world. Two of Neri's pictures from this latter group, respectively, show veins of gold and silver growing in the earth. The veins are depicted exactly like the arteries of an animal. In both pictures, they radiate out around fiery holes in the ground, what one might presume to be volcanos. Overhead the sun shines down on the gold and the moon over the silver. Further up in the sky, Neri shows the constellations associated with each metal; Leo the lion for gold and Cancer the crab for silver (his rendition looking more like a lobster).

It was no flight of fancy that mined metal and ore deposits were depicted as literal veins. It was widely thought these were living structures, which carried the earth’s nutrients. In one of Neri's final works, his 1613 manuscript Discorso, he explains the ancient theory that gold could occur as immature seed material, left over from the primordial creation. If properly nourished, this seed would mature and grow into the precious metal, and with the appropriate knowledge this natural process could be restarted, or accelerated and the gold could be brought to perfection by artificial means. 

Antonio Neri, "The Mineral Silver"
Neri 1598-2000 (Ferguson 67), f. 6r.
The idea that mined mineral deposits could regenerate naturally, if left to rest, is an ancient concept, one that persisted long past Neri’s era. In 1814, writing about tin mining in "On the Veins of Cornwall," William Phillips complained to the Geological Society of London, that armed with some current scientific knowledge, "nor would many miners […] believe, even to this day, in the regeneration of metals." Phillips quoted from an 1811 survey by
Tonkin, in Carew's survey of Cornwall: "Whether tin doth grow again, and fill up places which have been formerly wrought away, or whether it only seperateth itself from the consumed offal, hath been much controverted, and is not to this day decided." And  "whether—dead lodes—that have not one grain of tin in them—may not hereafter be impregnated,  matured,  and prove a future supply to the country, when the present lodes are exhausted, I think well deserves our highest consideration."  

At base, this is not superstition nor wild speculation, but rather considered judgments of thoughtful men making careful observations. Mines were often attended by acidic or other caustic liquids, either produced naturally or by washing operations, which leached out and dissolved various solubles. These liquids could sometimes dissolve metal out of ore and redeposit it elsewhere. Abandoned mines, it was noticed, could exhibit new crystal growth after a period of years or centuries. Today, the redeposition of minerals is a well accepted phenomenon, however, where it does occur it takes place not on a human time scale, but on a geological one, over millions of years.

*This post first appeared here in a slightly different form on 2 December 2013.

Friday, April 21, 2017

Zaffer

Antique Apothecary jars,
cobalt blue glass.
As best as I can remember, the first time that I really noticed glass was at four or five years old, at my grandmother's house in Queens, New York. The sunlight filtering through a low window caught my eye with a brilliant blue glint through a small cobalt glass bottle.  My grandmother held it up to the light for me and I was enchanted; transported into a realm of exquisite pure color.

Little did I know that the spell cast on me at such a young age had been cast on Egyptian pharaohs of the eighteenth dynasty and on Persian princesses, two thousands years ago, by their cobalt glass jewelry. In all three cases, the deep rich blue of cobalt oxide glass was responsible. Today, the source of ancient Middle Eastern cobalt is unknown, possibly West Africa, but more recently, in the Renaissance; it was mined in Hungary, in Bohemia and in German Saxony, where it was called "zaffer," after its sapphire color.

Legend tells that sixteenth century silver miners in Germany amassed a hoard of smaltite thinking it was silver ore. When they tried to smelt it, the arsenic which cobalt ores always have, evolved highly toxic fumes that made them sick. Discouraged and maligned, they said the product of their labors was cursed by goblins; they named it "kobald" (cobalt) after the evil spirits. The theme of 'evil spirits' (toxic fumes) was common in mining circles. A mythology persisted from ancient times up until the eighteenth century that divided the spirits into two groups; mischievous, and malevolent. The mischievous spirits played tricks on the miner's perception and equipment, the malevolent spirits could stop a man dead in his tracks, literally. 

Regardless of the difficulties both terestrial and otherwise, a strong market developed for the newly found "kobald" among artists for paint, potters for glazes, and glassmakers. The Saxon miners gained a reputation for producing the finest zaffer.

In his glassmaking book L'Arte Vetraria, Antonio Neri describes his method for purifying and preparing zaffer for use in glass. It is a recipe that would stand the test of time, still quoted by authors into the nineteenth and twentieth century.

To Prepare Zaffer, Which Serves for Many Colors in the Art of Glassmaking

You should get zaffer in large pieces and put it in earthenware oven-pans holding it in the furnace chamber for half a day. Then put it into iron ladles to inflame it in the furnace. Heat it well, then take and sprinkle it with strong vinegar. When cold, grind it finely over a porphyry stone into glazed earthen pots with hot water. Then wash more water over it always leaving the zaffer to settle in the bottom.

Now gently decant, to carry away the sediment and impurities of the zaffer. The good part and pigment of the zaffer will remain in the bottom. The pigment remains are now prepared and purified to be far better than it was at first, which will make clear and limpid pigment. This zaffer should be dried and kept in sealed vessels for use, which will be much improved over the original.


Until the mid 1700s zaffer had been associated with silver and copper mines, and was commonly thought to be a derivative of copper. It was Swedish chemist Georg Brandt who finally isolated the new metal, and gave it the name which honors the miners and the subterranean spirits which still can cast a spell on us through its deep pure blue color in glass.

* This post first appeared here in a slightly different form on 4 April 2014.

Friday, April 14, 2017

Primordial Matter

16th century Mining practices, 
from Agricola, De Re Metallica
In the early seventeenth century, Florentine priest Antonio Neri wrote the first printed book devoted to formulating glass from raw materials. His work is called L'Arte Vetraria, which translates to "the art of glassmaking." The book became quite famous and this is what he is remembered for today, yet he considered himself first and foremost an alchemist. In previous posts, we have explored the commonalities between glassmaking, medicine and the apothecary's trade. Another field closely connected to alchemy was mining. 

In the seventeenth century, the earth was considered a living entity; metals were found to occur in "veins" which were thought to grow and once mined, regenerate over time. The metals themselves were thought to undergo a maturation process. Primordial material left over from the creation of the world exerted its influence deep in the ground. Nurtured by the earth, under the influence of the suns rays, a process took place that eventually turned base metals into the more noble silver and gold. As far as Neri was concerned, alchemy was the art of imitating and enhancing natural processes that were already at work. In his manuscript Discorso, he writes:
I feel that the more perfect the art the most simple it is; so the authors [of alchemy] most unanimously agree that the ‘primordial material’ [prima materia] of the [philosopher’s] stone is something vile [base] and not bought with money, but easy to find. Moreover, the manner of work must imitate nature, which in order to produce gold makes use of the singular or simple material, which is the seed of gold, of a single vessel, which is the ‘womb of the earth’ [seno della terra] and of a single natural and vital fire, which is the sun.*
Elsewhere in the manuscript, Neri discusses several specific mines. He discusses the use of "vitriol" water that flowed in certain mines and how it could be used to transmute iron into copper. He discusses an unidentified mine "some distance from Leiden" and another in Slovakia in the town of Smolnik. It is reasonable to think that Neri visited these places himself. A third location, which he purposely keeps under wraps, is where he obtained "immature" gold that he was able to "multiply" through alchemical manipulation. With a certain disappointment, he writes "To this day I have never found another mine like it, and therefore suitable for this purpose." Clearly, he spent a significant portion of his time looking. He advises:
The gold mines are not all in the same condition, which is well understood for those of silver and all the other [metals]. Some are already perfect, in which nature has done what it could do and reduced the gold to its maturity, while other [mines] are still imperfect and in their infancy*
In his work for Medici prince Don Antonio in Florence, Neri's assistant/disciple was Agnolo della Casa. Della Casa took copious notes of Neri's experiments, and literally filled thousands of pages in notebooks that are today held by the National Library in Florence. Much of this material dealt with the transmutation of metals, and as we have seen Neri was not only concerned with materials, but with their specific place of origin. His first manuscript was titled "Treasure of the World, By Priest Antonio Neri – which [covers] the whole of alchemy with various illustrations, not only of the furnaces, vessels and chemical instruments but with other illustrations concerning the mining of all the metals." For he and his colleagues, mining and alchemy shared theoretical connections but also familial ones. Della Casa had a relative named Filippo Talducci della Casa (1543- c.1615), who was a celebrated alchemist and mining engineer, working in Prague and Krakow for the Holy Roman Emperor. Last but not least, there was also a practical connection. Mining provided many of the raw materials used in Antonio Neri’s glassmaking activities.  

* For a full discussion of Neri’s Discorso, see M. G. Grazzini, “Discorso sopra la Chimica: The Paracelsian Philosophy of Antonio Neri”, Nuncius 27, pp. 411-467.

** This post first appeared here 30 April 2014.