Natron
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Natron is a naturally occurring mixture of sodium carbonate decahydrate and around 17% sodium bicarbonate along with small quantities of sodium chloride and sodium sulfate. Natron is white to colourless when pure, varying to gray or yellow with... Wikipedia
Element symbol: Na
2V angle: Measured: 71°, Calculated: 80°
Category: Carbonate mineral
Crystal class: Prismatic (2/m); (same H-M symbol)
Crystal habit: crystalline, granular, and columnar crusts
Crystal system: Monoclinic
Formula (repeating unit): Na2CO3·10H2O