An overview on Sellaite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Sellaite gems.
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|Crystallography||Tetragonal: crystals prismatic, acicular, fibrous aggregates.|
|Cleavage||Poorly observed although literature indicates perfect in 2 directions. Fracture conchoidal; brittle.|
|Stone Sizes||The Brazilian sellaite is the w0rld‘s only extant cuttable material, and the largest crystals found thus far are only 5 cm long with small transparent areas. Thus, gems of only a few carats have or could be produced. This is an exceedingly rare gemstone, both in occurrence and number of cut stones.|
Optics: o=1.378; e= 1.390.
Occurrence: Sellaite occurs in a wide vaiiety of geologica environments.
Vesuvius, Italy: in volcanic fumaroles.
Harz Mountains, Germany: in evaporite beds.
Italy; France: in veins.
Nertschin, USSR: in pegmatites.
Oslo Region, Norway: cavities in a soda-granite.
Brumado Mine, Bahia, Brazil: gemmy crystals in a metamorphic magnesite deposit.
Name: After the Italian mining engineer and mineralogist, Quintino Sella.