Akrochordite

Akrochordite is a monoclinic-prismatic reddish-brown mineral containing arsenic, hydrogen, magnesium, manganese, and oxygen. It is an exceptionally rare hydrated hydrous arsenate mineral of the formula (Mn, Mg)4(AsO4)2(OH)4.4H2O and represents a small group of rare in the nature manganese (Mn) arsenates and, similarly to most other Mn-bearing arsenates, possess pinkish color. It is typically associated with metamorphic Mn deposits. It is a rare reddish-brown mineral typically found as small spherical aggregates in association with manganese ore.

General Information

  • Category: Phosphate minerals
  • Formua: (Mn, Mg)4(AsO4)2(OH)4.4H2O
  • Crystal system: Monoclinic
  • Crystal class: Prismatic (2/m)
  • Specific Gravity: 3.194 – 3.35

It is a rare mineral in hausmannite ore from a metamorphosed Fe-Mn orebody (Sweden); in a metamorphosed stratiform zinc orebody (Sterling Hill, New Jersey, USA).

  • Environment: A rare mineral in hausmannite ore from a metamorphosed Fe-Mn orebody (Långban, Sweden); in a metamorphosed stratiform zinc orebody (Sterling Hill, New Jersey, USA).
  • IMA Status: Valid Species (Pre-IMA) 1922
  • Locality: From Långban, Varmland, Sweden. At Sterling Hill, Ogdensburg, Sussex Co., New Jersey, USA. Link to MinDat.org Location Data.
  • Name Origin: From the Greek for wart, for its typical habit.

Identification

  • Color: Yellowish red-brown, pale to dark brown, pale pink
  • Cleavage: Perfect, On {010} a second, perpendicular to the first.
  • Tenacity: Brittle
  • Mohs scale hardness: 3.5
  • Luster: Sub-Vitreous, resinous, dull
  • Diaphaneity: Translucent
  • Density: 3.194 – 3.35 g/cm3 (Measured) and 3.26 g/cm3 (Calculated).

 

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