Thermonatrite

Formula: Na₂CO₃.H₂O

Origin of name: From Greek thermos = heat and natron

Crystal system: Orthorhombic

Crystal class: mm2

Twinning:

Unit cell: a = 10.72, b = 5.249, c = 6.469

Colour: Colourless, white, grayish, yellowish

Diaphaneity: Transparent to translucent

Luster: Vitreous - dull

Habit: crystals platy acicular very rare, typically as powdery crusts, efflorescence

Hardness: 1 to 1.5

Specific gravity: 2.26

Cleavage: 1; {100} difficult

Tenacity: Sectile

Streak: White

Synonyms/varieties:

Comments:  Found in dry lakes in arid regions. Soluble in water, alkaline taste, dehydrated readily.