Renierite
Renierite is a rare sulfide mineral that is not often faceted. It’s not difficult to facet, just not much demand for faceted Renierite gems. So from the point of availability, it is a very rare gem. Another one of those gems for “Black Gem” collectors. Renierite gems can have a beautiful iridescent appearance that the mineral is known for.
Although there are several sources of Renierite worldwide, it is a rare mineral. Some of the sources include the Prince Léopold mine, Kipushi, Katanga Province, Congo (Shaba Province, Zaire) [the Type Locality]; Pinar del Rio, Cuba; Tsumeb, Namibia; Kabwe (Broken Hill), Zambia; Chelopech deposit, Sofia, Bulgaria; San Giovanni mine, Iglesiente, Sardinia, Italy; Caucasus Mountains, Russia; Finnmark, Norway; Akita Prefecture, Japan; Udaipur district, Rajasthan, India; Ruby Creek deposit, southern Brooks Range, Alaska, USA; and Jamestown, Boulder County, Colorado, USA
| Crystallography: | Tetragonal – Scalenohedral |
| Crystal Habit: | As rare equant crystals, to 3 mm; disseminated granular aggregates, irregular patches, and as regular lamellae replacing germanite grains. |
| Twinning: | Polysynthetic twinning common; crystals are usually twinned |
| Cleavage: | None |
| Fracture: | Uneven |
| Tenacity: | Brittle |
| Hardness (Mohs): | 4.0 – 5.0 |
| Density: | 4.38 (g/cm3) |
| Luminescence: | None |
| Radioactivity: | Not Radioactive |
| Color: | Orange-Bronze, tarnishes Reddish |
| Transparency: | Opaque |
| Luster: | Metallic |
| Refractive Index: | n/a; Opaque Metallic |
| Birefringence: | n/a; Opaque Metallic |
| Dispersion: | n/a; Opaque Metallic |
| Pleochroism: | Orange to brown or bronze with a violet tint |
| Anisotropism: | Strong; Yellow to Reddish Orange |
| Other: | Magnetic |
