PURPURITE: Usakos, Namibia (specimens ~2 inches across). Photo © Joel E. Arem, PhD, FGA. Used with permission.
This material is never transparent and is too soft for wear. However, cabochons are a magnificent purplish rose hues that have essentially no counterpart in the gem world. The material is available from Namibia in abundance and at low cost.
| Data | Value |
|---|---|
| Name | Purpurite |
| Stone Sizes | Cabochons up to several inches long can be cut from cleavages. |
| Formula | (Mn,Fe)PO4. |
| Colors | Deep rose to reddish purple; alters on outside to brown or black. |
| Fracture | Uneven |
| Hardness | 4-4.5 |
| Cleavage | Good 1 direction |
| Crystallography | Orthorhombic. Crystals rare, in small masses and cleavages. |
| Refractive Index | 1.85-1.92 |
| Birefringence | 0.007 |
| Dispersion | Very strong. |
| Luminescence | None. |
| Luminescence Present | No |
| Absorption Spectrum | Not diagnostic. |
| Pleochroism | Strong: gray/rose-red or deep red/purplish red. |
| Optics | a = 1.85; β = 1.86; γ = 1.92. Biaxial (+), 2V moderate. |
| Optic Sign | Biaxial + |
| Luster | Dull, satiny. |
| Specific Gravity | 3.69. |
| Transparency | Translucent to opaque. |
Series to Heterosite.
Optics: a = 1.85; β=1.86; γ =1.92.
Biaxial (+), 2V moderate.
Occurrence: A secondary mineral, due to the oxidation of phosphates in granite pegmatites.
South Dakota; California; North Carolina.
France; Portugal; Western Australia.
Usakos, Namibia: rich purplish masses.
Comments: This material is never transparent and is too soft for wear. However, cabochons are a magnificent purplish rose hues that have essentially no counterpart in the gem world. The material is available from Namibia in abundance and at low cost.
Name: After the Latin purpura (purple), in allusion to the color.
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