Tincalconite (Borates)

Tincalconite hydrated sodium borate Na2B4O5(OH)4-3H2O
chalky white tincalconite crystals after borax			detail of same specimen (note: green and pink shadows are the result of light probes with different color temperatures

Diagnostic properties:

Color: chalky white.
Streak: white.
Hardness: 1.
Specific Gravity: 1.88.
Luster: dull, earthy.
Transparency: opaque.
Other properties: sweet-alkaline taste; an alteration product of borax.
Occurrence: rare.
Crystal system: hexagonal.
Uses: a source of boric acid.

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