Chrysocolla
Chrysocolla, or ‘gold-solder’, is a copper mineral with a long and colourful history. Today, the mineral is used as both a gemstone for jewellery and as a pigment for paint. It can be found in a variety of colours but only the brightest of greens and blues are selected to produce pigment. Chrysocolla, strictly copper hydroxide silicate (CuSiO3.nH2O), is noted for its hardness and brightness of colour retained even after grinding. The pigment is highly transparent with a low tinting strength and is most suitable for use in acrylics, tempera, watercolour, and gouache. This mineral has a long history as a pigment that has touched cultures across the world.
Chrysocolla was likely first mined in ancient Egypt. This activity was centred in Sinai and the eastern desert of what is now modern-day Egypt. Seti I (1313 BCE to 1292 BCE) and his successor Ramesses II (1292 to 1225 BCE) sent expeditions to the region of Nubia to look for gold which is likely when the mining of chrysocolla in Abu Seyal of the eastern desert may have begun. When the pharaoh Semerkhet (d. 2960 BCE) needed copper ore he sought it from Sinai. The history of chrysocolla in Egypt goes back further, however, with copper ore pigment found in eye paint in graves from 4000 BCE. Copper ore was rare in Egypt and in these historical mines, even the smallest of veins of the substance have been exhausted. It is clear that chrysocolla, among other copper minerals, must have been very valuable. Greek geographer and historian, Strabo (63 BCE – c. 24 CE) wrote that ‘there are also mines of copper, iron and gold’ in reference to Ethiopia. However, geography at the time was vague and he might have meant Egypt or Sudan. The mining and use of chrysocolla and other copper minerals in northeastern Africa has a long and sustained history that can now be seen in approximately one tonne of chrysocolla held in Egyptological exhibitions around the world today.
Chrysocolla Pigments
Image Credit: Master Pigments
Chrysocolla is among the three main pigments used to produce green paint in ancient Greece. The other two are malachite and verdigris; however, due to how the latter degrades only malachite and chrysocolla have been identified in excavations and we must trust the writings of naturalist, Theophrastus (371 - 287 BCE) on the manner and extent of use of verdigris in Greek antiquity. Roman naturalist Pliny the Elder (CE 23/24–79), also wrote about the use of chrysocolla to produce pigments. He wrote of Roman painters that “before applying the sandy variety they put on a preliminary coating of black dye and pure white chalk: these serve to hold the gold-solder and give a softness of colour. As the pure white chalk is of a very unctuous consistency and extremely tenacious owing to its smoothness, it is sprinkled with a coat of black, to prevent the extreme whiteness of the chalk from imparting a pale hue to the gold-solder.”
The name ‘gold-solder’ is a literal translation of the Greek name ‘chrysocolla’, from the Ancient Greek χρυσός (khrusós, “gold”) and κόλλα (kólla, “glue”). This name reveals to us more about the history of this mineral and its usage. Chrysocolla has also been used to solder gold and silver metal objects and at one time, among the wealthiest men of antiquity, chrysocolla would have been familiar in the detailing of fine metalware. In a drinking song, 7th-century BCE poet Alcman leaves to us a description of a finely dressed table on which, between seeded buns, sit chrysocolla-bound drinking cups. A few hundred years later, playwright Sophocles (c. 497 – 406 BCE) included in a play that only survives today as a fragment, solid silver cups soldered with chrysocolla as prizes at an athletic contest. While chrysocolla is a viable material for the soldering of gold and silver it becomes violent when it is heated and tends to eat through thin metal and mark heavier plate. Pliny writes about the process of ‘saterna’ in which chrysocolla was diluted with cyprian verdigris, child’s urine, and nitrum (naturally occurring compound of sodium carbonate, sodium bicarbonate, sodium chloride, and sodium sulphate, used as a flux in soldering). Etruscan jewellery has also been found with the use of chrysocolla as a gold-solder. It is from this technological application of the mineral that we take the name chrysocolla although it has not been applied in this manner since antiquity.
Chryzokola, polerowane zgłady (Durango) Meksyk
Image Credit: Adam Ognisty - Own work, CC BY 3.0, https://commons.wikimedia.org/w/index.php?curid=22069311
Continuing chronologically, we must look to Northern Chile to the Atacama Desert where chrysocolla and other copper compounds have been found in rock paintings. Chrysocolla is abundant in the mines of Calama and Quetena and the low-acid areas of the desert and has been mined for green pigment since pre-Hispanic times. Pigment making with chrysocolla in Chile became more common during the Late Intermediate Period (CE 900-1450) and continued into colonial times with large amounts of the pigment being exported to Europe by the Spanish. Historian León Pinelo, in the 17th century, noted that copper deposits in the Atacama highlands were being depleted as a result of mining for the production of blue pigments for painters in Caspana. Chrysocolla was culturally and economically significant to the region and this can be seen not only in surviving art but also in the large sites of waste ore, a byproduct of the processing of the stone.
Georg Agricola, a German humanist and mineralogist, listed chrysocolla as one of the most essential pigments used by painters in the 16th: chalk, red chalk, ochre, different earths, caeruleum, chrysocolla, armenium, verdigris, orpiment, violet fluorite, lead white, red lead, and vermillion. He categorised different types of chrysocolla based on the provenance of the mineral, its properties, and the method of its exploitation. He also gives a detailed account of the method of extraction of chrysocolla from the Hungarian mines in Neusohl by sedimentation. It is clear that although a significant amount of the mineral was being imported into Northern Europe from South America in the Renaissance period, there was already a well-established mining and trade of the material within Europe and the mineral already had a defined place in the European artist’s pallet. During the Renaissance, chrysocolla also became known as herbacea, meaning ‘leaf-green’, and it is from this name that the more contemporary name for the pigment was developed. Today the pigment will as often be labelled ‘chrysocolla’ as it will be ‘cedar green’ in pallets of watercolour, gouache, and acrylic paints.
Sources
Copper in Ancient Egypt, A. Lucas, The Journal of Egyptian Archaeology, Vol. 13, No. 3/4, 1927
Ancient Greek Pigments from the Agora, Earle R. Caley, Hesperia: The Journal of the American School of Classical Studies at Athens, Vol.14, No.2, The American Excavations in the Athenian Agora: Twenty-Sixth Report, 1945
Middle and Later Byzantine Wall Painting Methods. A Comparative Study., David C. Winfield, Dumbarton Oaks Papers, Vol.22, 1968
https://www.kremer-pigmente.com/en/shop/pigments/10350-chrysocolla.html
A Classification for Granulation in Ancient Metalwork, Dian Lee Carroll, American Journal of Archaeology, Vol. 78, No.1, 1974
Writing on Pigments in Natural History and Art Technology in Sixteenth-Century Germany and Switzerland, Doris Oltrogge, Early Science and Medicine, Vol. 20, No. 4/6, Special Issue: Early Modern Color Worlds, 2015
Copper Pigment-Making In The Atacama Desert (Northern Chile), Marcela Sepulveda R., Valentina Figueroa L., and Sandrine Pages-Camagna, Latin American Antiquity, Vol. 24, No.4, 2013
Images
https://www.masterpigments.com/chrysocolla-pigments/?srsltid=AfmBOoo9UeqhoOOPcOgM9jDOWrsLSC_JGUu9SbQHlIeKydInvESvw8dk
https://commons.wikimedia.org/wiki/Category:Chrysocolla#/media/File:'_chryzokola'.jpg
Cover Image
Parent Géry, Own Work
https://commons.wikimedia.org/wiki/File:Atacamite,_chrysocolle.jpg
