Mineral Species: Antlerite

Chemical Formula: Cu3SO4(OH)4

Chemical Name: Copper Sulfate Hydroxide 

Mineral Class: Sulfate

Mineral Notes: Antlerite has been an important ore of copper and forms in the oxidation zones of primary copper deposits. It typically occurs as tabular, acicular or fibrous crystals. The latter often form aggregates of randomly organized coatings and tufts. The green colour is usually a deep and attractive shade. Once thought to be a rare mineral, Antlerite was discovered to be the main copper ore at the Chuquicamata mines in Chile. The mineral can be confused with Malachite or Brochantite. This raises a number of identification problems. However whilst Malachite will bubble in warm HCl, Antlerite will not. Brochantite is all but indistinguishable by ordinary means although its terminations are typically more rounded. 

Description: Plates of green Antlerite on a grey matrix. Magnifcation shows high crystal form composed of mats of overlapping tabular crystals. There are also numerous dark green crystals having flattened acicular form. The contast between the two colours and forms of the mineral is unusual, both occurring in a single specimen.

Location: Piesky, Spania Dolina, Slovakia.