Molybdenite

Formula:  MoS₂

Origin of name:  From Greek molybdos - lead

Crystal system:  Hexagonal

Crystal class:  6/m 2/m 2/m

Twinning: 

Unit cell: a = 3.161 Å, c = 12.30 Å

Colour:  Lead-gray

Diaphaneity: 

Luster:  Metallic

Habit:  Crystals thin to thick tabular, hexagonal aspect; short barrel-shaped prisms; foliated or radiate masses; scales; grains

Hardness:  1 to 1.5

Specific gravity:  4.62 to 5.06

Cleavage:  1; {0001} perfect, easy

Tenacity:  Laminae flexible; sectile

Streak:  Greenish

Synonyms/varieties:  Plumbago

Comments:  Data are for molybdenite-2H; there is also a -3R polytype; dimorphous with jordisite