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  Formula: Bi2Se3
  
  Selenide, stibnite group, 
  paramorph of 
  paraguanajuatite, 
  bismuth-bearing mineral
  
  Crystal System: Orthorhombic
  
  Specific gravity: 6.25 to 6.98 measured, 7.54 calculated
  
  Hardness: 2½ to 3
  
  Streak: Shiny grey
  
  Colour: Bluish grey
  
  Common impurities: S
  
  Environments
  
  Guanajuatite occurs in hydrothermal deposits of low to medium temperatures. Associated minerals include 
  bismuthinite, bismuth, 
  clausthalite, nevskite, 
  galena, pyrite and 
  calcite 
  (HOM).
  
  Localities
  
  At the Buraco do Ouro mine, Cavalcante, Goiás, Brazil, kalungaite 
  occurs in a quartz-muscovite 
  mylonite, related to a peraluminous 
  granite, in platy anhedral aggregates along foliation planes. 
  Associated ore minerals include gold, 
  chalcopyrite, 
  bohdanowiczite, 
  clausthalite, guanajuatite, 
  stibiopalladinite, 
  sperrylite and padmaite. 
  Gangue minerals are muscovite, 
  quartz and rare tourmaline and 
  magnetite  
  (MM 70.1.123–130).
  
  The type locality is the Santa Catarina mine, Rancho Calvillo, Santa Rosa, Sierra de Santa Rosa, Guanajuato Municipality, 
  Guanajuato, Mexico.
  
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