Anhydrite Value, Price, and Jewelry Information


Anhydrite
By Rock Currier (http://www.mindat.org/photo-217328.html) [CC-BY-3.0], via Wikimedia Commons

The blue or violet color disappears on heating and can be restored by gamma ray bombardment. The natural color may therefore be caused by natural radiation. Gemstones are very fragile due to excellent cleavages and must be cut and handled with great care.

Anhydrite Value

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

Anhydrite Information

DataValue
NameAnhydrite
Crystallography Orthorhombic. Crystals equant, thick, tabular or (rarely) prismatic; massive, cleavable.
Colors Colorless, white-gray, bluish, violet, pinkish, reddish, brownish.
Luster Greasy; pearly on cleavage; vitreous in massive varieties.
Hardness 3-3.5
Specific Gravity 2.9-2.98
Birefringence 0.044
Cleavage Perfect 1 direction, nearly perfect 1 direction
Dispersion 0.013
Stone SizesFaceted gems are quite unusual, usually small (1-5 carats), but potentially much larger. Gems up to 9 carats have been cut, but cleavage masses could provided larger rough. Faceted gems are usually purplish or pale pink from the Swiss and Canadian localities. PC: 2.86 (pink-blue bicolor, Bancroft).
Luminescence Red color in LW (Germany)
Spectral Not diagnostic
Formula CaSO4
Pleochroism  In violet crystals: colorless-pale yellow/ pale violet-rse/violet.

Optics: α = 1.570; β = 1.575 γ= 1.614.

Biaxial (+), 2V ~43°

Occurrence: A rock-forming mineral, associated with gypsum beds, halite, and limestones. Also occurs in hydrothermal veins, cavities in basalts, and other traprocks.

South Dakota, New Mexico, New Jersey, Texas, Nova Scotia

France, India, Germany, Austria, Poland.

Faraday Mine, Bancroft, Ontario, Canada: large purplish masses, some facetable.

Simplon Tunnel, Switzerland: pale purple cleavages, facetable.

Mexico: large blue masses, very lovely color.

Volpino, Italy: a white-gray, marble like textured material known as vulpinite and locally used as a decorative stone and made into cabochons.

Comments: The blue or violet color disappears on heating and can be restored by gamma ray bombardment. The natural color may therefore be caused by natural radiation. Gemstones are very fragile due to excellent cleavages and must be cut and handled with great care.

Names: Greek without water, in allusion to composition.