Chrysoprase

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Decanter
MFA# 1998.400

Description

Arts & Crafts brooch
MFA# 2008.264

A translucent, apple-green stone composed of microcrystalline Quartz. Chrysoprase is a variety of Chalcedony that contains small amounts of hydrated nickel silicate. The gemstone has occasionally been found in Egyptian, Greek, and Roman jewelry. Chrysoprase was also valued for mural decorations.

Synonyms and Related Terms

chalcedony; crisoprásio (Port.); Chrysopras (Deut.)

Physical and Chemical Properties

  • No visible crystals
  • Fracture = conchoidal, granular
  • Luster = waxy to greasy
  • Streak = white
  • Fluorescence = generally inert
  • Pleochroism = absent
Composition SiO2
Mohs Hardness 6.0-7.0
Density 2.65-2.91 g/ml
Refractive index 1.535 - 1.539
Birefringence 0.004 - 0.009

Comparisons

Properties of Common Gemstones

Resources and Citations

  • Gem Identification Lab Manual, Gemological Institute of America, 2016.
  • Mineralogy Database: Quartz
  • Jack Odgen, Jewellery of the Ancient World, Rizzoli International Publications Inc., New York City, 1982
  • A.Lucas, J.R.Harris, Ancient Egyptian Materials and Industries, Edward Arnold Publishers Ltd., London, 4th edition, 1962
  • C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
  • G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 647
  • Wikipedia: Chrysoprase Accessed Dec 2022.