Sellaite Value, Price, and Jewelry Information


Sellaite
Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC-BY-SA-3.0], via Wikimedia Commons

An overview on Sellaite Jewelry and Gemstones. Covers details and essential information on the physical properties and characteristics of Sellaite gems.

Sellaite Value

The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.

Sellaite Information

DataValue
NameSellaite
Crystallography Tetragonal: crystals prismatic, acicular, fibrous aggregates.
Colors Colorless, white.
Luster Vitreous.
Fracture Conchoidal; brittle.
Hardness 5-5 .5.
Specific Gravity 3.15.
Birefringence 0.012.
Cleavage Poorly observed although literature indicates perfect in 2 directions.
Stone SizesThe Brazilian sellaite is the world‘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.
Luminescence None reported.
Spectral None.
FormulaMgF2.
Pleochroism None.

Optics: o=1.378; e= 1.390.

Uniaxial (+).

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.