ANHYDRITE

HISTORY, NAME, LOCALITIES: Mineralogists recognized anhydrite as a distinct species in 1794 after realizing that the mineral’s composition did not include water, but was otherwise identical to that of gypsum.  Its name stems from the Greek anydros, meaning “without water,” alluding to its anhydrous state.  The most notable occurrence is in Mexico’s Naica Mine where individual crystals reach 34 feet in length.  Other localities are in Canada, Austria, Germany, Italy, Peru, and the United States (Texas, Louisiana, New Mexico).

MINERALOGY, PROPERTIES, OCCURRENCE: Anhydrite [calcium sulfate, CaSO₄], pronounced ann-HIGH-drite, crystallizes in the orthorhombic system.  It usually occurs in massive form, but occasionally develops tabular or prismatic prisms.  Anhydrite is most often white or colorless, but impurities can create a range of pale hues.  It has a hardness of Mohs 3.0-3.5, perfect cleavage in one direction, vitreous luster, and a specific gravity of 2.97.  Anhydrite forms primarily as layers in evaporite beds, often in association with gypsum, and to a lesser extent as a secondary mineral in geodes.

METAPHYSICAL PROPERTIES, LORE, USES: Metaphysical practitioners believe that pale-blue anhydrite can remove emotional blocks, especially those regarding resentment.  Anhydrite has no technological uses.

COLLECTORS’ INFORMATION: Anhydrite is collected for the rarity of its crystal forms.  The most desirable specimens consist of groups of elongated crystals in parallel or near-parallel alignment and with distinctive, flat terminations.