Bobierrite

Formula:  Mg₃(PO₄)₂ ^. 8H₂O

Origin of name:  For P. Bobierre, French chemist

Crystal system:  Monoclinic

Crystal class:  2/m

Twinning:

Unit cell: a = 9.97 Ǻ, b = 27.71 Ǻ, c = 4.65 Ǻ, β = 104.2°

Colour:  Colourless, white

Diaphaneity:  Transparent

Luster:  Vitreous

Habit:  Crystals minute acicular or fibrous; massive, lamellar, flattened or crystalline aggregates

Hardness:  2 to 2.5

Specific gravity:  2.195

Cleavage:  1; {010} perfect

Tenacity:

Streak:

Synonyms/varieties:

Comments:  Related to manganese-hoernesite and vivianite