Formula: MgAl2(PO4)2(OH)2
Origin of name: From Persian, lazhward = blue
Crystal system: Monoclinic
Crystal class: 2/m
Twinning: Common on {100}, may be polysynthetic or lamellar; rare on {223}
Unit cell: a = 7.15 Ǻ, b = 7.28 Ǻ, c = 7.23 Ǻ, β = 120.5°
Colour: Deep azure blue to light blue, bluish green
Diaphaneity:
Luster: Vitreous to dull
Habit: Crystals acute pyramidal, sometimes tabular; massive, compact to granular
Hardness: 5.5 to 6
Specific gravity: 3.10
Cleavage: 2; {110} indistinct to good; {101} indistinct
Tenacity: Uneven to splintery; brittle
Streak:
Synonyms/varieties: Gersbyite
Comments: Series with scorzalite
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