Olivine
Description
An olive green color magnesium iron silicate mineral. Olivine occurs in igneous and metamorphic rocks and has two compositional varieties: Fayalite (iron rich) and forsterite (magnesium rich). Olivine beads have been found in pre-Dynastic Egyptian jewelry. The opaque stone was found in Egypt, in the lava of Vesuvius and in the Eifel district of Germany. Transparent, gem quality stones, called Peridot, come from Zabargad (St. John's Island in the Red Sea) and from Minas Gerais (Brazil), South Africa, Myanmar (formerly Burma), Norway, British Columbia, and the U.S.(Arizona, Hawaii).
Synonyms and Related Terms
chrysolite; peridot (yellow-green); fayalite (Fe2SiO4); forsterite (Mg2SiO4); Olivin (Deut.); olivino (Esp.); peridoto (Esp.); olivine (Fr.); olivijn (Ned.); oliwin (Pol.); olivina (Port.)
Physical and Chemical Properties
- Orthorhombic crystal system with massive or granular forms
- Fracture = uneven to conchoidal
- Luster = vitreous
- Streak = colorless
- Transparent to translucent
- Fluorescence = none
- Pleochroism = weak yellow-green and green (noticeable only in dark stones)
| Composition | (Mg,Fe)2SiO4 |
|---|---|
| CAS | 1317-71-1 |
| Mohs Hardness | 6.5 - 7.0 |
| Density | 3.27-3.37 g/ml |
| Refractive Index | 1.64 - 1.70 |
| Birefringence | 0.035 - 0.040 |
Comparisons
Properties of Common Gemstones
Resources and Citations
- B.Aston, J.Harrell, I.Shaw, "Stone" in Ancient Egyptian Materials and Technology, P.Nicholson, I.Shaw (eds.), Cambridge University Press, 2000, p. 47-48.
- Gem Identification Lab Manual, Gemological Institute of America, 2016.
- Mineralogy Database: Olivine
- Jack Odgen, Jewellery of the Ancient World, Rizzoli International Publications Inc., New York City, 1982
- R.F.Symmes, T.T.Harding, Paul Taylor, Rocks, Fossils and Gems, DK Publishing, Inc., New York City, 1997
- C.W.Chesterman, K.E.Lowe, Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf, New York, 1979
- Wikipedia: Olivine (Accessed Nov. 9, 2005 and Dec 2022)
- 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
- Encyclopedia Britannica, http://www.britannica.com Comment: "olivine." Accessed 9 Dec. 2004 .
- The American Heritage Dictionary or Encarta, via Microsoft Bookshelf 98, Microsoft Corp., 1998
- G.S.Brady, Materials Handbook, McGraw-Hill Book Co., New York, 1971 Comment: p. 561
- Richard S. Lewis, Hawley's Condensed Chemical Dictionary, Van Nostrand Reinhold, New York, 10th ed., 1993