HEMIMORPHITE: Zacatecas, Mexico (~3 inches high)
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.
Hemimorphite Value
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Hemimorphite Information
| Data | Value |
| Name | Hemimorphite |
| Crystallography | Orthorhombic. Crystals tabular and thin, striated; fan-shaped aggregates. |
| Colors | White, colorless, pale blue, greenish, gray, yellowish, brown. |
| Luster | Vitreous, silky; dull. |
| Hardness | 4.5-5 |
| Density | 3.4-3.5 |
| Birefringence | 0.022 |
| 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). |
| Luminescence | None observed |
| Spectral | Not diagnostic. |
| Formula | Zn4SiO7(OH)2· H20. |
| Pleochroism | None |
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.
HEMIMORPHITE:
Mexico (0.75)
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.
