Sherwoodite

Formula: Ca₉Al₂V₄V₂₄O₈₀.56H₂O

Origin of name: for A. Sherwood, American chemist

Crystal system: tetragonal

Crystal class: 4/m 2/m 2/m

Twinning:

Unit cell: 

Colour: dark blue-black, blue-green to yellow-green when altered

Diaphaneity: 

Luster: vitreous to earthy

Habit: crystals equant or slightly flattened, polycrystalline aggregates

Hardness: about 2

Specific gravity: 2.8

Cleavage: none

Tenacity: 

Streak: 

Synonyms/varieties:

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