Mineral Information and Data:

Alpersite
(Mg,Cu2+)SO4 • 7H2O [CNMNC approved formula]

Named after Charles N. Alpers, geochemist with the United States Geological Survey, who has made significant contributions to our understanding of the mineralogical controls of mine -water geochemistry.

IMA status : Approved Species 2003 (IMA2003-040)
CLASSIFICATION 
Dana
(8th edition) :
29.06.10.06  
  (29) Hydrated Acid and Sulfates
  (29.06) where A XO4 · x(H2O)
  (29.06.10) Melanterite Group (Heptahydrates, Monoclinic: P21/c)
  
Nickel-Strunz
(10th edition) :
07.CB.35
  (07) Sulfates (selenates, tellurates, chromates, molybdates, wolframates)
  (07.C) Sulfates (selenates, etc.) without Additional Anions, with H2O
  (07.CB) With only medium-sized cations
  
Crystal system: Monoclinic System
Point group (H-M): 2/m — prismatic
Unit cell: a = 14.166 Å, b = 6.534 Å, c = 10.838 Å, b = 105.922°
  
Color: Blue
Diaphaneity: Transparent
Luster: Vitreous
Hardness (Mohs): 2.5
Cleavage: 1; {001} Good
Tenacity: Brittle
Fracture: Uneven
Streak: White
  
Geologic Setting: Formed from acid mine waste waters with mineralogically zoned assemblages in sheltered areas at a relative humidity of 65% and T = 4 °C. Dehydrates to cuprian pentahydrate. Mg-domin ant analog of melanterite.
  

 

Alpersite
Bright blue efforescence associated with pickeringite, alunogen, and epsomite. Pickeringite and alunogen (white and yellow) occur on top of a matte of alpersite (blue) adjacent to a concrete wall.
Origin: Big Mike mine, Nevada, USA.
Picture size 50 cm
Photo: © American Mineralogist

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