Mineral Information and Data:

Allochalcoselite
Cu1+Cu2+5PbO2(SeO3)2Cl5 [CNMNC approved formula]

Named from the Greek άλλος ("allos"), for "different", χαλκός ("chalkos") for "copper" and the element Selenium, to reflect the different valences and crystallographic behavior of copper in this selenite mineral.

IMA status : Approved Species 2004 (IMA2004-025)
CLASSIFICATION 
Dana
(8th edition) :
34.06.10.01  (This Dana# Added)
  (34) Selenites - Tellurites - Sulfites
  (34.06)
  (34.06.10)
  
Nickel-Strunz
(10th edition) :
04.JG.40
  (04) Oxides and Hydroxides
  (04.J) Arsenites, Antimonites, Bismuthites, Sulfites,
  (04.JG) Selenites with additional anions, without H2O
  
Crystal system: Monoclinic System
Point group (H-M): 2/m — prismatic
Unit cell: a = 18.468 Å, b = 6.1475 Å, c = 15.314 Å, b = 119.284°
Crystal Habit: Encrustations - Forms crust-like aggregates on matrix.
  
Color: Dark brown
Diaphaneity: Translucent
Luster: Adamantine
Hardness (Mohs): 3 - 4
Measured Density: 4.653 (calculated) g/cm3
Cleavage: 1: {100} Perfect
Tenacity: Brittle
Streak: Brown
  
Geologic Setting: Found among lead and copper selenite-chloride exhalative products associated with the fumaroles.
  

<<< BACK TO MINERAL SEARCH