Dioptase Crystals on Duftite Matrix

Dioptase is a rare and striking mineral known for its vibrant emerald-green to bluish-green color. It’s a cyclosilicate mineral with the chemical formula CuSiO₃·H₂O, containing copper, silicon, oxygen, and water.

Dioptase on Duftite, From Tsumeb, Namibia. Photography by: Joy Desor

The mineral occurs in the oxidized zones of copper deposits, often associated with minerals such as malachite and chrysocolla. Notable localities include Tsumeb, Namibia; Altyn-Tyube, Kazakhstan; and the Mammoth-St. Anthony Mine in Arizona, USA.

Key Characteristics:

• Formula: Cu₆Si₆O₁₈·6H₂O
• System: Trigonal
• Colour: Emerald Green, blue-green
• Lustre: Vitreous
• Hardness: 5

Fun Fact:

Despite its stunning color, dioptase is not a practical source of copper due to its rarity and the small amounts of copper it contains.