Tags: Chemical Substance, Mineral.
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 crystal system and has been found as primary euhedral di-rhombohedral pseudo-octahedral crystals. It is also found pseudomorphically replacing borax crystals.
