Euchroite: Properties and Occurrences

Euchroite is a hydrated copper arsenate hydroxide mineral with formula: Cu2AsO4OH·3H2O. It is a vitreous green to emerald green mineral crystallizing in the orthorhombic system. It was Named in reference to its beautiful emerald green color after the Greek words eu, used as a prefix to mean “fair” or “good,” and, chroma, meaning “color.

It is a very rare mineral in the oxidized zone of some copper-bearing hydrothermal mineral deposits.

General Information

  • Category: Arsenate minerals
  • Formula: Cu2AsO4OH·3H2O
  • Crystal system: Orthorhombic
  • Crystal class: Disphenoidal (222)

Properties

It has a Mohs hardness of 3.5 – 4.0 and a specific gravity of 3.39 – 3.45. It was first described in 1823 in Ľubietová, Slovakia.

  • Color: Leek green, Emerald green.
  • Density: 3.39 – 3.45, Average = 3.42
  • Diaphaneity: Transparent to translucent
  • Hardness: 3.5-4 – Copper Penny-Fluorite
  • Luminescence: Non-fluorescent.
  • Luster: Vitreous (Glassy)
  • Streak: green

Occurrence

Euchroite is a rare mineral that can be found in localities in Slovakia, Greece, Bulgaria, the United States, and others and occurs in oxidized copper-bearing hydrothermal deposits.

Association: Olivenite (Lubietov´a, Slovakia); strashimirite, olivenite, azurite, malachite (Zapachitsa deposit, Bulgaria).

 

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