Barite

Formula:  BaSO₄

Origin of name:  From Greek for heavy

Crystal system:  Orthorhombic

Crystal class:  2/m 2/m 2/m

Twinning:

Unit cell: a = 7.156 Ǻ, b = 8.881 Ǻ, c = 5.454 Ǻ

Colour:  Colourless, white to greyish, yellowish to brown, bluish

Diaphaneity:

Luster:  Vitreous to resinous

Habit:  Crystals thin to thick tabular; short to long prismatic equant; aggregates, stalactitic, columnar, fibrous earthy

Hardness:  3 to 3.5

Specific gravity:  4.50

Cleavage:  3; {001} perfect, {210} distinct, {010} imperfect

Tenacity:  Uneven; brittle

Streak:

Synonyms/varieties:  Baryte, hokutolite (Pb-rich var.)

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