Cupellation
Encyclopedia
Cupellation is a metallurgical process in which ores
or alloy
ed metal
s are treated under high temperatures and carefully controlled operations in order to separate noble metals, like gold
and silver
, from base metals like lead
, copper
, zinc
, arsenic
, antimony
or bismuth
, that might be present in the ore. This process is based on the principle that precious metals do not oxidise or react chemically, contrary to what happens to the base metals; so that when they are heated at high temperatures, the precious metals remain apart and the others react forming slag
s or other compounds.
Since the Early Bronze Age, the process of cupellation was used to obtain silver
out of smelted lead ores; by the Middle Ages
and the Renaissance
it was one of the most common and important processes used to refine metals. By then, fire assays were used for mineral assaying, testing fresh metals such as lead and recycled metals to know their purity (jewellery
) and minting
. Cupellation principles have always remained the same, they change only in the amount of material processed. It is still in use today based on the same principles.
is a rare element, although it exists as such. Most of the time it is found in nature combined with other metals and minerals that contain silver compounds, generally in the form of sulfides such as galena
(lead sulfide) or cerussite
(lead carbonate). So the primary production of silver was and is done by the smelting of argentiferous lead ores which are subsequently cupelled.
Lead melts at 327°C while silver melts at 960°C; when mixed, as in galena, the most common argentiferous lead ore, they have to be smelted at high temperatures in a reducing condition to produce argentiferous lead. The metal then has to be melted again at high temperatures of the order of 900°C or 1000°C in a hearth or blast furnace where air flow makes possible the oxidation of the lead. Lead transforms into lead oxide
(PbO) known as litharge
, which captures the oxides of the rest of the metals, while silver and gold remain on top of the liquid litharge. The latter is removed or absorbed by capillary action
into the hearth linings.This chemical reaction may be viewed as (Ag+Cu) + Pb + O2 → (CuO+PbO) + Ag
The base of the hearth was dug in the form of a sauce pan and covered with an inert and porous material rich in calcium
or magnesium
such as shells or lime or by wood or bone ash. The necessity of lining with calcareous materials was due to the fact that lead reacts with silica (clay compounds) to form lead silicate with a viscous nature that will not allow the litharge to be absorbed in the correct way. Calcareous materials do not react with lead. Some of the litharge fumes evaporate and the rest, in a liquid state are absorbed by the porous earth linings which form what it is known as litharge cakes.
Litharge cakes are usually in the shape of circular, concavo-convex cakes of approximately 15 cm in diameter and are the most common archaeological evidence of the cupellation process in the Early Bronze Age. By their chemical composition, archaeometallurgists may know what kind of ore was treated, which were the main components in it or which steps might have been followed in the process. This information might give them insights about production process, trade, social needs or economic situations among others.
the use of the cupellation processes was diverse: assay of ores from the mines, testing the amount of silver in jewels or coins or for experimental purposes. It was carried out in small shallow recipients known as cupels.
As the main purpose of small scale cupellation was to assay and test minerals and metals, the matter to be tested has to be carefully weighed. The assays were made in the cupellation or assay furnace, which needs to have windows and bellows to ascertain that the air oxidises the lead
, as well as to be sure and prepared to take away the cupel when the process is over. Pure lead has to be added to the matter being tested to guarantee the further separation of the impurities. After the litharge
has been absorbed by the cupel, buttons of silver were formed and settled in the middle of the cupel. If the alloy also contained a certain amount of gold, it settled with the silver
and both had to be separated by parting
.
, the best material was obtained from burned horns of deer although fish spines could work well. Ashes have to be ground into a fine and homogeneous powder and mixed with some sticky substance to mould the cupels. Moulds were made out of brass
with no bottoms so that the cupels could be taken off. A shallow depression in the centre of the cupel was made with a rounded pestle. Cupel sizes depend on the amount of material to be assayed. This same shape has been maintained until the present.
Archaeological investigations as well as archaeometallurgical
analysis and written texts from the Renaissance
have demonstrated the existence of different materials for their manufacture; they could be made also with mixtures of bones and wood ashes, which were not of a very high quality, or moulded with a mixture of this kind in the bottom with an upper layer of bone ashes. Different recipes depend on the expertise of the assayer or on the special purpose for which it was made (assays for minting
, jewelry, testing purity of recycled material or coins). Archaeological evidence shows that at the beginnings of small scale cupellation, potsherds or clay cupels were used.
in Anatolia
and Mesopotamia
during the 4th and 3rd millennium BC., the Early Bronze Age. Archaeological findings of silver and lead objects together with litharge pieces and slag
have been studied in a variety of sites, and metallurgical analysis suggests that by then people were confidently extracting silver from lead ores so the method would have been known earlier.
During the following Iron Age
, cupellation was done by fusing
the debased metals with a surplus of lead, the bullion or result product of this fusion was then heated in a cupellation furnace to separate the noble metals. Mines such as Rio Tinto
, near Huelva in Spain
, started to be an important political and economic site for many people around the Mediterranean Sea
, as well as Laurion in Greece
. Around 500 B.C. control over the Laurion mines gave Athens
political advantage and power in the Mediterranean so that they were able to defeat the Persians
.
During the Roman
times, the empire needed large quantities of lead in order to support the Roman civilization over a great territory; they searched for open lead-silver mines in whatever area they conquered. Silver coin
age became the normalised media for exchange, therefore silver production and mine control gave economic and political power. In Roman times it was worth mining lead ores if their content of silver was 0.01% or more.
It is not known with certainty when or where cupellation was used as an analytical tool for the first time. One of the earliest written references of cupels may be on Theophilus Divers Ars back in the 12th century AD. In the Middle Ages there is not much information about the development of the process. Descriptions of cupels by then were very similar to those of the 16th century.
Small-scale cupellation may be considered as the most important fire assay developed in history and many think of it as the origin of chemical analysis. Most of the written evidence comes from the Renaissance
in the 16th century. Georg Agricola
and Lazarus Ercker, among others, wrote about the art of mining and testing the ores, as well as detailed descriptions about the cupellation process and the ways in which it should be done. Their descriptions and assumptions have been identified within diverse archaeological findings through Medieval and Renaissance Europe. By these times the amount of fire assays increased considerably, mainly because of testing the ores in the mines in order to identify the availability of its exploitation. A primary use of cupellation was related to minting activities, and it was also used in testing jewelry. Since the Renaissance, cupellation became a standardised method of analysis that has changed very little, demonstrating its efficiency. Its development certainly touched the spheres of economy, politics, warfare and power in ancient times.
, Bolivia
and Ecuador
make us wonder whether the pre-Hispanic civilizations obtained the raw material from native ores or from argentiferous-lead ores. Although native silver may be available in America
, it is as rare as in the Old World
. From colonial
texts it is known that silver mines were open in colonial times by the Spaniards from Mexico
to Argentina
, the main ones, being those of Tasco, Mexico
and Potosí
in Bolivia.
Some kind of blast furnaces called huayrachinas were described in colonial texts, as native technology furnaces used in Perú
and Bolivia
to smelt the ores that come from the silver mines owned by the Spaniards. Although it is not conclusive, it is believed that these kinds of furnaces may have been used before the Spanish Conquest. Ethnoarchaeological
and archaeological works done at Porco – Potosí, Bolivia
have suggested it.
There are no specific archaeological accounts about silver smelting
or mining
in the Andes
prior to the Incas. However, silver and lead artefacts have been found in the Peruvian central highlands dated in the pre-Inca and Inca periods. From the presence of lead in silver artefacts, archaeologists suggest that the cupellation process might have occurred there.
Orés
Orés is a municipality in the Cinco Villas, in the province of Zaragoza, in the autonomous community of Aragon, Spain. It belongs to the comarca of Cinco Villas. It is placed 104 km to the northwest of the provincial capital city, Zaragoza. Its coordinates are: 42° 17' N, 1° 00' W, and is...
or alloy
Alloy
An alloy is a mixture or metallic solid solution composed of two or more elements. Complete solid solution alloys give single solid phase microstructure, while partial solutions give two or more phases that may or may not be homogeneous in distribution, depending on thermal history...
ed metal
Metal
A metal , is an element, compound, or alloy that is a good conductor of both electricity and heat. Metals are usually malleable and shiny, that is they reflect most of incident light...
s are treated under high temperatures and carefully controlled operations in order to separate noble metals, like gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
and silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
, from base metals like lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
, copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
, zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
, arsenic
Arsenic
Arsenic is a chemical element with the symbol As, atomic number 33 and relative atomic mass 74.92. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. It was first documented by Albertus Magnus in 1250.Arsenic is a metalloid...
, antimony
Antimony
Antimony is a toxic chemical element with the symbol Sb and an atomic number of 51. A lustrous grey metalloid, it is found in nature mainly as the sulfide mineral stibnite...
or bismuth
Bismuth
Bismuth is a chemical element with symbol Bi and atomic number 83. Bismuth, a trivalent poor metal, chemically resembles arsenic and antimony. Elemental bismuth may occur naturally uncombined, although its sulfide and oxide form important commercial ores. The free element is 86% as dense as lead...
, that might be present in the ore. This process is based on the principle that precious metals do not oxidise or react chemically, contrary to what happens to the base metals; so that when they are heated at high temperatures, the precious metals remain apart and the others react forming slag
Slag
Slag is a partially vitreous by-product of smelting ore to separate the metal fraction from the unwanted fraction. It can usually be considered to be a mixture of metal oxides and silicon dioxide. However, slags can contain metal sulfides and metal atoms in the elemental form...
s or other compounds.
Since the Early Bronze Age, the process of cupellation was used to obtain silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
out of smelted lead ores; by the Middle Ages
Middle Ages
The Middle Ages is a periodization of European history from the 5th century to the 15th century. The Middle Ages follows the fall of the Western Roman Empire in 476 and precedes the Early Modern Era. It is the middle period of a three-period division of Western history: Classic, Medieval and Modern...
and the Renaissance
Renaissance
The Renaissance was a cultural movement that spanned roughly the 14th to the 17th century, beginning in Italy in the Late Middle Ages and later spreading to the rest of Europe. The term is also used more loosely to refer to the historical era, but since the changes of the Renaissance were not...
it was one of the most common and important processes used to refine metals. By then, fire assays were used for mineral assaying, testing fresh metals such as lead and recycled metals to know their purity (jewellery
Jewellery
Jewellery or jewelry is a form of personal adornment, such as brooches, rings, necklaces, earrings, and bracelets.With some exceptions, such as medical alert bracelets or military dog tags, jewellery normally differs from other items of personal adornment in that it has no other purpose than to...
) and minting
Coin
A coin is a piece of hard material that is standardized in weight, is produced in large quantities in order to facilitate trade, and primarily can be used as a legal tender token for commerce in the designated country, region, or territory....
. Cupellation principles have always remained the same, they change only in the amount of material processed. It is still in use today based on the same principles.
Large Scale Cupellation
Native silverSilver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
is a rare element, although it exists as such. Most of the time it is found in nature combined with other metals and minerals that contain silver compounds, generally in the form of sulfides such as galena
Galena
Galena is the natural mineral form of lead sulfide. It is the most important lead ore mineral.Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms...
(lead sulfide) or cerussite
Cerussite
Cerussite is a mineral consisting of lead carbonate , and an important ore of lead. The name is from the Latin cerussa, white lead. Cerussa nativa was mentioned by Conrad Gessner in 1565, and in 1832 F. S. Beudant applied the name cruse to the mineral, whilst the present form, cerussite, is due to...
(lead carbonate). So the primary production of silver was and is done by the smelting of argentiferous lead ores which are subsequently cupelled.
Lead melts at 327°C while silver melts at 960°C; when mixed, as in galena, the most common argentiferous lead ore, they have to be smelted at high temperatures in a reducing condition to produce argentiferous lead. The metal then has to be melted again at high temperatures of the order of 900°C or 1000°C in a hearth or blast furnace where air flow makes possible the oxidation of the lead. Lead transforms into lead oxide
Lead oxide
Lead oxide may refer to:* Lead oxide, PbO, litharge, massicot* Lead oxide, Pb3O4, minium, red lead* Lead dioxide , PbO2Less common lead oxides are:* Lead oxide, Pb2O3, lead sesquioxide...
(PbO) known as litharge
Litharge
Litharge is one of the natural mineral forms of lead oxide, PbO. Litharge is a secondary mineral which forms from the oxidation of galena ores. It forms as coatings and encrustations with internal tetragonal crystal structure. It is dimorphous with the orthorhombic form massicot...
, which captures the oxides of the rest of the metals, while silver and gold remain on top of the liquid litharge. The latter is removed or absorbed by capillary action
Capillary action
Capillary action, or capilarity, is the ability of a liquid to flow against gravity where liquid spontanously rise in a narrow space such as between the hair of a paint-brush, in a thin tube, or in porous material such as paper or in some non-porous material such as liquified carbon fiber, or in a...
into the hearth linings.This chemical reaction may be viewed as (Ag+Cu) + Pb + O2 → (CuO+PbO) + Ag
The base of the hearth was dug in the form of a sauce pan and covered with an inert and porous material rich in calcium
Calcium
Calcium is the chemical element with the symbol Ca and atomic number 20. It has an atomic mass of 40.078 amu. Calcium is a soft gray alkaline earth metal, and is the fifth-most-abundant element by mass in the Earth's crust...
or magnesium
Magnesium
Magnesium is a chemical element with the symbol Mg, atomic number 12, and common oxidation number +2. It is an alkaline earth metal and the eighth most abundant element in the Earth's crust and ninth in the known universe as a whole...
such as shells or lime or by wood or bone ash. The necessity of lining with calcareous materials was due to the fact that lead reacts with silica (clay compounds) to form lead silicate with a viscous nature that will not allow the litharge to be absorbed in the correct way. Calcareous materials do not react with lead. Some of the litharge fumes evaporate and the rest, in a liquid state are absorbed by the porous earth linings which form what it is known as litharge cakes.
Litharge cakes are usually in the shape of circular, concavo-convex cakes of approximately 15 cm in diameter and are the most common archaeological evidence of the cupellation process in the Early Bronze Age. By their chemical composition, archaeometallurgists may know what kind of ore was treated, which were the main components in it or which steps might have been followed in the process. This information might give them insights about production process, trade, social needs or economic situations among others.
Small scale cupellation
Small scale cupellation is based on the same principle as the one done in a cupellation hearth; the main difference lies in the amount of material to be tested or obtained. The minerals have to be crushed, roasted and smelted to concentrate the metallic components in order to separate the noble metals. By the RenaissanceRenaissance
The Renaissance was a cultural movement that spanned roughly the 14th to the 17th century, beginning in Italy in the Late Middle Ages and later spreading to the rest of Europe. The term is also used more loosely to refer to the historical era, but since the changes of the Renaissance were not...
the use of the cupellation processes was diverse: assay of ores from the mines, testing the amount of silver in jewels or coins or for experimental purposes. It was carried out in small shallow recipients known as cupels.
As the main purpose of small scale cupellation was to assay and test minerals and metals, the matter to be tested has to be carefully weighed. The assays were made in the cupellation or assay furnace, which needs to have windows and bellows to ascertain that the air oxidises the lead
Lead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
, as well as to be sure and prepared to take away the cupel when the process is over. Pure lead has to be added to the matter being tested to guarantee the further separation of the impurities. After the litharge
Litharge
Litharge is one of the natural mineral forms of lead oxide, PbO. Litharge is a secondary mineral which forms from the oxidation of galena ores. It forms as coatings and encrustations with internal tetragonal crystal structure. It is dimorphous with the orthorhombic form massicot...
has been absorbed by the cupel, buttons of silver were formed and settled in the middle of the cupel. If the alloy also contained a certain amount of gold, it settled with the silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
and both had to be separated by parting
Gold parting
Gold parting is the separating of gold from silver. Gold and silver are often extracted from the same ores and are chemically similar and therefore hard to separate. Over the centuries special means of separation have been invented...
.
Cupels
The primary tool for small scale cupellation was the cupel. Their manufacture was made in a very careful way. They used to be small vessels shaped in the form of an inverted truncated cone, made out of bone ashes. According to Georg AgricolaGeorg Agricola
Georgius Agricola was a German scholar and scientist. Known as "the father of mineralogy", he was born at Glauchau in Saxony. His real name was Georg Pawer; Agricola is the Latinised version of his name, Pawer meaning "farmer"...
, the best material was obtained from burned horns of deer although fish spines could work well. Ashes have to be ground into a fine and homogeneous powder and mixed with some sticky substance to mould the cupels. Moulds were made out of brass
Brass
Brass is an alloy of copper and zinc; the proportions of zinc and copper can be varied to create a range of brasses with varying properties.In comparison, bronze is principally an alloy of copper and tin...
with no bottoms so that the cupels could be taken off. A shallow depression in the centre of the cupel was made with a rounded pestle. Cupel sizes depend on the amount of material to be assayed. This same shape has been maintained until the present.
Archaeological investigations as well as archaeometallurgical
Archaeometallurgy
Archaeometallurgy is the study of the history and prehistory of metals and their use through humans. It is a sub-discipline of archaeology and archaeological science...
analysis and written texts from the Renaissance
Renaissance
The Renaissance was a cultural movement that spanned roughly the 14th to the 17th century, beginning in Italy in the Late Middle Ages and later spreading to the rest of Europe. The term is also used more loosely to refer to the historical era, but since the changes of the Renaissance were not...
have demonstrated the existence of different materials for their manufacture; they could be made also with mixtures of bones and wood ashes, which were not of a very high quality, or moulded with a mixture of this kind in the bottom with an upper layer of bone ashes. Different recipes depend on the expertise of the assayer or on the special purpose for which it was made (assays for minting
Minting
Minting is a small village and civil parish just off the A158 road, in the East Lindsey district of Lincolnshire, England.Minting is one of the Thankful Villages that suffered no fatalities during the Great War of 1914 to 1918....
, jewelry, testing purity of recycled material or coins). Archaeological evidence shows that at the beginnings of small scale cupellation, potsherds or clay cupels were used.
History
The first known use of silver was in the Near EastNear East
The Near East is a geographical term that covers different countries for geographers, archeologists, and historians, on the one hand, and for political scientists, economists, and journalists, on the other...
in Anatolia
Anatolia
Anatolia is a geographic and historical term denoting the westernmost protrusion of Asia, comprising the majority of the Republic of Turkey...
and Mesopotamia
Mesopotamia
Mesopotamia is a toponym for the area of the Tigris–Euphrates river system, largely corresponding to modern-day Iraq, northeastern Syria, southeastern Turkey and southwestern Iran.Widely considered to be the cradle of civilization, Bronze Age Mesopotamia included Sumer and the...
during the 4th and 3rd millennium BC., the Early Bronze Age. Archaeological findings of silver and lead objects together with litharge pieces and slag
Slag
Slag is a partially vitreous by-product of smelting ore to separate the metal fraction from the unwanted fraction. It can usually be considered to be a mixture of metal oxides and silicon dioxide. However, slags can contain metal sulfides and metal atoms in the elemental form...
have been studied in a variety of sites, and metallurgical analysis suggests that by then people were confidently extracting silver from lead ores so the method would have been known earlier.
During the following Iron Age
Iron Age
The Iron Age is the archaeological period generally occurring after the Bronze Age, marked by the prevalent use of iron. The early period of the age is characterized by the widespread use of iron or steel. The adoption of such material coincided with other changes in society, including differing...
, cupellation was done by fusing
Fusing
For the art, see stained glass fusing.Fusing is a type of manufacturing process for joining or terminating electrical magnet wire, that is coated with a varnish type insulation, to itself or some type of electrical terminal, without prior removal of the insulation. During the fusing process, the...
the debased metals with a surplus of lead, the bullion or result product of this fusion was then heated in a cupellation furnace to separate the noble metals. Mines such as Rio Tinto
Rio Tinto Group
The Rio Tinto Group is a diversified, British-Australian, multinational mining and resources group with headquarters in London and Melbourne. The company was founded in 1873, when a multinational consortium of investors purchased a mine complex on the Rio Tinto river, in Huelva, Spain from the...
, near Huelva in Spain
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
, started to be an important political and economic site for many people around the Mediterranean Sea
Mediterranean Sea
The Mediterranean Sea is a sea connected to the Atlantic Ocean surrounded by the Mediterranean region and almost completely enclosed by land: on the north by Anatolia and Europe, on the south by North Africa, and on the east by the Levant...
, as well as Laurion in Greece
Greece
Greece , officially the Hellenic Republic , and historically Hellas or the Republic of Greece in English, is a country in southeastern Europe....
. Around 500 B.C. control over the Laurion mines gave Athens
Athens
Athens , is the capital and largest city of Greece. Athens dominates the Attica region and is one of the world's oldest cities, as its recorded history spans around 3,400 years. Classical Athens was a powerful city-state...
political advantage and power in the Mediterranean so that they were able to defeat the Persians
Persian people
The Persian people are part of the Iranian peoples who speak the modern Persian language and closely akin Iranian dialects and languages. The origin of the ethnic Iranian/Persian peoples are traced to the Ancient Iranian peoples, who were part of the ancient Indo-Iranians and themselves part of...
.
During the Roman
Ancient Rome
Ancient Rome was a thriving civilization that grew on the Italian Peninsula as early as the 8th century BC. Located along the Mediterranean Sea and centered on the city of Rome, it expanded to one of the largest empires in the ancient world....
times, the empire needed large quantities of lead in order to support the Roman civilization over a great territory; they searched for open lead-silver mines in whatever area they conquered. Silver coin
Coin
A coin is a piece of hard material that is standardized in weight, is produced in large quantities in order to facilitate trade, and primarily can be used as a legal tender token for commerce in the designated country, region, or territory....
age became the normalised media for exchange, therefore silver production and mine control gave economic and political power. In Roman times it was worth mining lead ores if their content of silver was 0.01% or more.
It is not known with certainty when or where cupellation was used as an analytical tool for the first time. One of the earliest written references of cupels may be on Theophilus Divers Ars back in the 12th century AD. In the Middle Ages there is not much information about the development of the process. Descriptions of cupels by then were very similar to those of the 16th century.
Small-scale cupellation may be considered as the most important fire assay developed in history and many think of it as the origin of chemical analysis. Most of the written evidence comes from the Renaissance
Renaissance
The Renaissance was a cultural movement that spanned roughly the 14th to the 17th century, beginning in Italy in the Late Middle Ages and later spreading to the rest of Europe. The term is also used more loosely to refer to the historical era, but since the changes of the Renaissance were not...
in the 16th century. Georg Agricola
Georg Agricola
Georgius Agricola was a German scholar and scientist. Known as "the father of mineralogy", he was born at Glauchau in Saxony. His real name was Georg Pawer; Agricola is the Latinised version of his name, Pawer meaning "farmer"...
and Lazarus Ercker, among others, wrote about the art of mining and testing the ores, as well as detailed descriptions about the cupellation process and the ways in which it should be done. Their descriptions and assumptions have been identified within diverse archaeological findings through Medieval and Renaissance Europe. By these times the amount of fire assays increased considerably, mainly because of testing the ores in the mines in order to identify the availability of its exploitation. A primary use of cupellation was related to minting activities, and it was also used in testing jewelry. Since the Renaissance, cupellation became a standardised method of analysis that has changed very little, demonstrating its efficiency. Its development certainly touched the spheres of economy, politics, warfare and power in ancient times.
Cupellation in the New World
The huge amount of Pre-Hispanic silver adornments known especially from PerúPeru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
, Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
and Ecuador
Ecuador
Ecuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...
make us wonder whether the pre-Hispanic civilizations obtained the raw material from native ores or from argentiferous-lead ores. Although native silver may be available in America
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, it is as rare as in the Old World
Old World
The Old World consists of those parts of the world known to classical antiquity and the European Middle Ages. It is used in the context of, and contrast with, the "New World" ....
. From colonial
Colony
In politics and history, a colony is a territory under the immediate political control of a state. For colonies in antiquity, city-states would often found their own colonies. Some colonies were historically countries, while others were territories without definite statehood from their inception....
texts it is known that silver mines were open in colonial times by the Spaniards from Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
to Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
, the main ones, being those of Tasco, Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
and Potosí
Potosí
Potosí is a city and the capital of the department of Potosí in Bolivia. It is one of the highest cities in the world by elevation at a nominal . and it was the location of the Spanish colonial mint, now the National Mint of Bolivia...
in Bolivia.
Some kind of blast furnaces called huayrachinas were described in colonial texts, as native technology furnaces used in Perú
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
and Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
to smelt the ores that come from the silver mines owned by the Spaniards. Although it is not conclusive, it is believed that these kinds of furnaces may have been used before the Spanish Conquest. Ethnoarchaeological
Ethnoarchaeology
Ethnoarchaeology is the ethnographic study of peoples for archaeological reasons, usually through the study of the material remains of a society . Ethnoarchaeology aids archaeologists in reconstructing ancient lifeways by studying the material and non-material traditions of modern societies...
and archaeological works done at Porco – Potosí, Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
have suggested it.
There are no specific archaeological accounts about silver smelting
Smelting
Smelting is a form of extractive metallurgy; its main use is to produce a metal from its ore. This includes iron extraction from iron ore, and copper extraction and other base metals from their ores...
or mining
Mining
Mining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
in the Andes
Andes
The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...
prior to the Incas. However, silver and lead artefacts have been found in the Peruvian central highlands dated in the pre-Inca and Inca periods. From the presence of lead in silver artefacts, archaeologists suggest that the cupellation process might have occurred there.
See also
- AlchemyAlchemyAlchemy is an influential philosophical tradition whose early practitioners’ claims to profound powers were known from antiquity. The defining objectives of alchemy are varied; these include the creation of the fabled philosopher's stone possessing powers including the capability of turning base...
- History of alchemy
- Archaeometry
- Georgius Agricola
- Philosopher's stonePhilosopher's stoneThe philosopher's stone is a legendary alchemical substance said to be capable of turning base metals into gold or silver. It was also sometimes believed to be an elixir of life, useful for rejuvenation and possibly for achieving immortality. For many centuries, it was the most sought-after goal...
- History of ChemistryHistory of chemistryBy 1000 BC, ancient civilizations used technologies that would eventually form the basis of the various branches of chemistry. Examples include extracting metals from ores, making pottery and glazes, fermenting beer and wine, making pigments for cosmetics and painting, extracting chemicals from...
- MetallurgyMetallurgyMetallurgy is a domain of materials science that studies the physical and chemical behavior of metallic elements, their intermetallic compounds, and their mixtures, which are called alloys. It is also the technology of metals: the way in which science is applied to their practical use...
- MiningMiningMining is the extraction of valuable minerals or other geological materials from the earth, from an ore body, vein or seam. The term also includes the removal of soil. Materials recovered by mining include base metals, precious metals, iron, uranium, coal, diamonds, limestone, oil shale, rock...
External links
- Porco-Potosí archaeological project http://lamar.colostate.edu/~mvanbure/index.htm
- http://www.ancientgreece.com/essay/v/laurion_and_thorikos/
- http://people.hsc.edu/drjclassics/sites/thorikos/9801.htm
- http://whc.unesco.org/en/tentativelists/1789/
- http://searchworks.stanford.edu/view/993825
- http://www.gabrielbernat.es/colonia/mineria/html/potosi.html
- http://www.riotinto.com/
- http://galileo.rice.edu/Catalog/NewFiles/ercker.html
- Söderberg, A. 2011. Eyvind Skáldaspillir's silver - refining and standards in pre-monetary economies in the light of finds from Sigtuna and Gotland. Situne Dei 2011. Edberg, R. Wikström, A. (eds). Sigtuna.