Hemimorphite is very rare as a faceted gemstone. Suitable material is known only from Mexico thus far. The massive blue material is a very delicate color, but is seldom cut because not very much has appeared on the market.
The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
|Crystallography||Orthorhombic. Crystals tabular and thin, striated; fan-shaped aggregates.|
|Colors||White, colorless, pale blue, greenish, gray, yellowish, brown.|
|Luster||Vitreous, silky; dull.|
|Cleavage||Perfect 1 direction. Fracture even to subconchoidal. Brittle.|
|Stone Sizes||Blue massive material cut as cabochons to several inches in length. Colorless material from Mexico in faceted gems 1-3 carats; larger stones are very rare. Devonian Group (Calgary, Alberta, Canada): 1.90 (colorless, Mexico).|
Optics: a = 1.614; β= 1.617; γ= 1.636.
Biaxial (+), 2V= 46°.
Occurrence: A secondary mineral in the oxide zones of ore deposits.
Found throughout the southwestern United States and Mexico: various localities worldwide.
Mexico: crystals up to several inches in length are found at Mapimi, Durango, and Santa Eulalia, Chihuahua; some of these are transparent and will yield stones up to ~ 7-10 carats. Also found as blue crusts.
Comments: Hemimorphite is very rare as a faceted gemstone. Suitable material is known only from Mexico thus far. The massive blue material is a very delicate color, but is seldom cut because not very much has appeared on the market.
Name: In allusion to crystal forms.