Pirssonite

Formula: Na₂Ca(CO₃)₂.2H₂O

Origin of name: for L. Pirsson, American mineralogist

Crystal system: orthorhombic

Crystal class: mm2

Twinning: 

Unit cell: a = 11.32 Å, b = 20.26 Å, c = 6.00 Å

Colour: colourless, white, grayish

Diaphaneity: transparent

Luster: vitreous

Habit: crystals short prismatic, elongated parallel to c-axis, tabular or pyramidal

Hardness: 3 to 3.5

Specific gravity: 2.352

Cleavage: none

Tenacity: 

Streak: 

Synonyms/varieties:

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