Locality: Mesopotamia 504, Copper Valley, Khorixas, Damaraland District, Kunene Region, Namibia (Locality at mindat.org) Size: 2.9 x 2.6 x 2.1 cm. Shattuckite is very rare in crystalline form. This new find from the area of Khorixas, in a remote part of Namibia known for scheelite in the past, is surprising. This is a superb specimen with a rich carpeting of beautiful crystals. By Rob Lavinsky, iRocks.com – CC-BY-SA-3.0 [CC-BY-SA-3.0], via Wikimedia Commons
Highest values go to finer blue colors.
The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
| Data | Value |
|---|---|
| Name | Shattuckite |
| Colors | Blue of various shades. |
| Crystallography | Orthorhombic. Crystals slender prismatic; massive, granular; fibrous. |
| Refractive Index | 1.752-1.815 |
| Luster | Vitreous to silky. |
| Polish Luster | Vitreous to silky. |
| Hardness | 3.5 |
| Fracture | Uneven to splintery |
| Specific Gravity | 3.8-4.11 |
| Birefringence | 0.063 |
| Cleavage | Very good in 2 directions |
| Stone Sizes | Only cabochons can be cut, up to several inches in length. |
| Luminescence | None. |
| Luminescence Present | No |
| Transparency | Translucent to opaque. |
| Absorption Spectrum | Not diagnostic. |
| Formula |
Cu§(Si01)4(OH)2. |
| Pleochroism |
None. |
| Optics |
a = 1.752-1.753; β = 1.782; γ = 1.815. Mean refractive index 1.75. Biaxial (+), 2V = 88°. |
| Optic Sign | Biaxial + |
a = 1.752-1.753; β= 1.782; γ=1.815. Mean refractive index 1.75.
Biaxial (+), 2V: 88°.
An alteration product of secondary copper minerals.
Shattuckite is often mixed with quartz, and data often reported for properties may be erroneous. The cabochons are rich blue in color and very popular, but the material is not abundant and seldom seen on the market.
Often mixed with quartz. Primary source Shattuck Mine, Bisbee Arizona.
Shattuckite is often confused with plancheite, which has recently been identified as a separate species, formula Cu8(Si4O11)2(OH)4 . xH20 There is no method of distinguishing between these species with common instruments. Gems must be sent to a major lab for positive identification.
From the Arizona locality, the Shattuck Mine. Recent studies have shown that plancheite, a mineral similar to and often confused with shattuckite, is a distinct species. The formula of plancheite is: Cu8(Si4O11)2(OH)4 ·Xh2O.
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