Hedyphane

Formula:  Pb₃Ca₂(AsO₄)₃Cl

Origin of name:   From Greek hedy - bright and phainomal - appear

Crystal system:   Hexagonal

Crystal class:  6/m

Twinning: 

Unit cell: a = 10.14 Ǻ, c = 7.185 Ǻ

Colour:  White, buff, yellowish white, bluish

Diaphaneity: 

Luster:  Bright, greasy to resinous

Habit:   Crystals prismatic or pyramidal to thick tabular; massive, coarse granular

Hardness:  4.5

Specific gravity:  5.82

Cleavage:  1; {10-11}

Tenacity:  Subconchoidal; brittle

Streak: 

Synonyms/varieties:  Pleonectite

Comments: