1. 
   Tincalconite
   Tincalconite is a hydrous sodium borate mineral closely related to borax, and is a secondary mineral that forms as a dehydration product of borax. Its formula is Na2B4O7·5H2O or Na2[B4O5(OH)4]·3H2O. Tincalconite typically occurs as a fine grained white powder. It crystallizes in the hexagonal cry...
   Found op http://en.wikipedia.org/wiki/Tincalconite
   
   
2. 
   tincalconite
   a borate mineral, hydrated sodium tetraborate (Na2B4O5(OH)43H2O), that is found in nature only as a dull, white, fine-grained powder; colourless ... [1 related articles]
   Found op http://www.britannica.com/eb/a-z/t/52
   
   

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