Chrysocolla

From CAMEO
Jump to navigation Jump to search
Chrysocolla

Description

Chrysocolla

A sky blue mineral composed of hydrated copper silicate. Chrysocolla is a secondary copper ore that has also been used as a Gemstone and a blue-green pigment. It has been gathered or mined as a semiprecious stone since 3000 BCE. Chrysocolla is mined in England (Cornwall, Cumberland), Congo, Zaire, Chile, and the U.S. (Pennsylvania, Arizona, New Mexico and Utah). The translucent to opaque stone is sky-blue in its natural state, but appears green when ground into a fine powder. Chrysocolla has been found as a pigment in wall painting at Kizil in Turkistan and in Twelfth Dynasty Egyptian tombs (Gettens and Stout 1966). In the 16th and 17th centuries, it was used as a watercolor pigment called cedar green. Chrysocolla is stable to light but is decomposed by acids, alkalis, and heat.

Synonyms and Related Terms

cedar green; copper silicate; gold solder; chryzokola (Pol.); crisocola (Port.); Chrysokoll (Deut.); chrysocolle (Fr.); chryssokolla (Gr.); crisocolla (It.); crisocola (Esp., Port.); chrysocolla (Ned.)

FTIR

Chrysocolla, Gila County AZ.PNG

Raman

Chrysocolla531.jpg


Physical and Chemical Properties

  • Luster = vitreous to dull.
  • Fracture = uneven to conchoidal.
  • Streak = white or pale blue-green.
  • Pigment particles are anisotropic with high birefringence, straight extinction and are pleochroic changing from pale green to colorless
Composition CuSiO3-nH2O
Mohs Hardness 2 - 4
Density 2.0-2.8 g/ml
Refractive Index 1.575; 1.598; 1.597

Comparisons

Characteristics of Common Blue Pigments

Resources and Citations

  • Nicholas Eastaugh, Valentine Walsh, Tracey Chaplin, Ruth Siddall, Pigment Compendium, Elsevier Butterworth-Heinemann, Oxford, 2004
  • R. J. Gettens, G.L. Stout, Painting Materials, A Short Encyclopaedia, Dover Publications, New York, 1966 Comment: density =2.4, ref. index=1.575; 1.598; 1.59
  • R.D. Harley, Artists' Pigments c. 1600-1835, Butterworth Scientific, London, 1982
  • Jack Odgen, Jewellery of the Ancient World, Rizzoli International Publications Inc., New York City, 1982
  • Kurt Wehlte, The Materials and Techniques of Painting, Van Nostrand Reinhold Co., New York, 1975 Comment: p. 52
  • C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
  • Thomas B. Brill, Light Its Interaction with Art and Antiquities, Plenum Press, New York City, 1980 Comment: ref.index.1.575; 1.598; 1.597
  • Encyclopedia Britannica, http://www.britannica.com Comment: Chrysocolla. Retrieved May 25, 2003. (tech info-ref. index = 1.45; 1.55)
  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 232
  • Van Nostrand's Scientific Encyclopedia, Douglas M. Considine (ed.), Van Nostrand Reinhold, New York, 1976
  • Random House, Webster's Encyclopedic Unabridged Dictionary of the English Language, Grammercy Book, New York, 1997