Otavite

Otavite is a rare cadmium carbonate mineral with the chemical formula CdCO₃. It is a member of the calcite group of minerals, which are all carbonates with a similar structure. Otavite typically occurs as rhombohedral crystals, often in drusy crusts or as massive aggregates.

Properties

• Color: Typically pink, reddish-brown, or yellowish-brown, but can also be colorless or white. The color is often due to impurities.
• Luster: Vitreous (glassy)
• Streak: White
• Hardness: 3.5 - 4 on the Mohs scale
• Density: 5.04 - 5.08 g/cm³
• Crystal System: Trigonal
• Cleavage: Perfect on {1011}
• Fracture: Conchoidal
• Transparency: Transparent to translucent
• Solubility: Soluble in dilute acids

Occurrence

Otavite is a secondary mineral that forms in the oxidized zones of cadmium-bearing ore deposits. It is typically found in association with other cadmium minerals, such as greenockite (CdS), and with other carbonate minerals, such as calcite and dolomite. Notable occurrences include the Tsumeb mine in Namibia, Broken Hill in Australia, and various locations in Europe and North America.

Uses

Otavite is primarily a mineral specimen for collectors due to its rarity and attractive color. While cadmium compounds have industrial uses, otavite itself is not commonly mined for cadmium extraction due to its scarcity.

Distinguishing Features

Otavite can be distinguished from other carbonate minerals by its relatively high density and its association with cadmium-bearing ore deposits. Its pink or reddish-brown color is also distinctive. X-ray diffraction analysis is often used for definitive identification.