Mineral Information and Data:

Althausite
Mg2PO4(OH) [CNMNC approved formula]

Named to honor Professor Egon Althaus (1933- ), Karlsruhe University, Karlsruhe, Germany.

IMA status : Approved Species 1975 (IMA1974-050)
CLASSIFICATION 
Dana
(8th edition) :
41.06.05.01  
  (41) Anhydrous Phosphates Containing Hydroxyl or Halogen
  (41.06) where (A)2 (XO4) Zq
  (41.06.05)
  
Nickel-Strunz
(10th edition) :
08.BB.25
  (08) Phosphates, Arsenates, Vanadates
  (08.B) Phosphates, etc. with Additional Anions, without H2O
  (08.BB) With only medium-sized cations, (OH, etc.):RO4 about 1:1
  
Crystal system: Orthorhombic System
Point group (H-M): mm2 — pyramidal
Unit cell: a = 8.258 Å, b = 6.054 Å, c = 14.383 Å
Crystal Habit: Cleavable masses
  
Color: Light gray, reddish brown
Diaphaneity: Translucent
Luster: Vitreous
Hardness (Mohs): 3.5 - 4
Measured Density: 2.97 g/cm3
Cleavage: 2; {001}perfect; {101} distinct
Streak: White
  
Polymorphism and Series: Dimorphous with holtedahlite.
Geologic Setting: In serpentine–magnesite deposits (Norway).
Mineral Association: Apatite, magnetite, xenotime, holtedahlite, szaibelyite, talc, magnesite (Tingelstadtjern quarry, Norway); apatite, enstatite, talc, magnesite (Overntjern quarry, Norway); fluorapatite, wolfeite, topaz, muscovite, sphalerite, quartz, chalcopyrite, pyrrhotite, siderite, arsenopyrite, chlorite, vivianite, panasqueiraite, thadeuite (Panasqueira, Portugal)
  

 

Althausite
Origin: Overntjern, Buskerud, Norway
Sample size: 3.2 x 5 cm specimen. Numerous 0.5 cm grayish to maroon colored and opaque crystals of althausite are found on this specimen
Photo: John Veevaert, Trinity Mineral Co

 

Althausite
(zoom-in of above)

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