Niedermayrite: Properties and Occurrences

Niedermayrite is a rare monoclinic hydrated copper cadmium sulfate hydroxide mineral. It is a rare hydrated copper cadmium sulfate hydroxide mineral with formula: Cu4Cd(SO4)2(OH)6·4H2O. It crystallizes in the monoclinic system and occurs as encrustations and well-formed vitreous blue-green prismatic crystals. It has a specific gravity of 3.36.

Niedermayrite was named for Gerhard Niedermayr (born 1941), an Austrian mineralogist. It was first described in 1998 from a mine in the Lavrion District, Attica, Greece. It is also reported from the Ophir District, Tooele County, Utah. The environment is in brecciated marble. The cadmium dominant analogue of campigliaite.

General Information

  • Category: Sulfate mineral
  • Formula: (repeating unit) Cu4Cd(SO4)2(OH)6·4H2O
  • Crystal system: Monoclinic
  • Crystal class: Prismatic (2/m) (same H-M symbol)
  • Color: Bluish green.

Properties

Niedermayrite is non-fluorescent and has a bluish-green colour with vitreous lustre, the streak is white.

  • Crystal habit: Platy euhedral crystals and as green crusts
  • Cleavage: Perfect on {010}
  • Tenacity: Brittle
  • Luster: Vitreous
  • Streak: White
  • Diaphaneity: Transparent
  • Specific gravity: 3.292
  • Optical properties: Biaxial (-)

Occurrence:

Very rare in the oxidation zone of a zinc-rich hydrothermal orebody in brecciated marble, formed as an alteration product of chalcopyrite and greenockite.

Association: Gypsum, malachite, chalcanthite, brochantite, hemimorphite, hydrozincite, aurichalcite, monteponite, otavite, sphalerite, greenockite, hawleyite, pyrite, galena.

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