Clinoclase

ClinoclaseClinoclase is quite a rare mineral that belongs to the class of phosphates. The first specimens were found in XIX c. in the Wheal Gorland mine situated in the territory of Cornwell, a peninsula in England. The name comes from the Greek words ‘klineis? and ‘klas? ? ‘decline? and ‘break’, due to the skew of the basal cleavage. In 1830, the term ‘clinoclase? was first introduced by A. Breithaupt, the famous German scientist in the field of mineralogy. The extraordinary beautiful stone has some other names – abichite, clinoclasite and aphanesite.

The gem’s chemical formula is Cu3 [AsO4] (OH) 3. The compound is dimorphic and occurs in nature as the gilmarite mineral. Clinoclase is a secondary mineral, copper arsenate hydroxide. The crystal system is monoclinic. The stone’s color can be blue, bluish-green and dark green. It is translucent. The cleavage plane is iridescent. The mineral is characterized by perfect cleavage and conchoidal fracture. The element is fragile. The streak is greenish blue. The hardness is quite low – 2.5-3. The specific gravity is 4.4 g/cm3.

ClinoclaseClinoclase is characterized by distinct pleochroism, acquiring greenish-blue and dark green shades. It melts easily when exposed to the blowpipe flame. While heated it releases an unpleasant smell of garlic typical of arsenic. The stone is soluble in acids and ammonia. The mineral is characterized by the relatively strong optic axis dispersion. Radioactivity is 0. The mineral mainly occurs in crystals of prismatic, tabular and orthorhombic structure. Besides, the mineral can form dense fibrous masses, crusts, efflorescence and radially fibrous aggregate. It can sometimes occur in magnificent fanlike rosettes and crystal-jams.

The mineral is formed in the zones of copper sulfide deposits oxidation. Associated minerals are azurite, brochantite, malachite, olivenite, conichalcite, liroconite, adamite ,quartz and limonite. Clinoclase is mined in the copper mineralization zone located in the Middle Urals, near Nizhny Tagil. The extraordinary beautiful crystals are found in Chile, the USA, England (Cornwall Peninsula). Specimens of the mineral are also found in Austria, Germany, the Czech Republic, Italy, Slovakia, Spain, France, Mexico, Namibia, and Australia.

Source: jevel.ru