Geocronite

Formula:  Pb₁₄(Sb,As)₆S₂₃

Origin of name:  From Greek for earth and Saturn, the alchemistic name for lead.

Crystal system:  Monoclinic

Crystal class:  2/m

Twinning:  On {001}, lamellar

Unit cell: a = 8.96 Ǻ, b = 31.93 Ǻ, c = 8.50 Ǻ, β = 118.0°

Colour:  Galena-white; may have greenish, bluish green or olive tinge, blue gray, gray

Diaphaneity: Opaque

Luster:  Metallic

Habit:  Crystals tabular; massive, granular, earthy

Hardness:  2.5

Specific gravity:  6.4

Cleavage:  1; {100} indistinct

Tenacity:  Uneven

Streak:  White with tinge same

Synonyms/varieties: Kilbrickenite

Comments:  Series with jordanite