Gold

Formula:  Au

Origin of name:   From German geld

Crystal system:  Cubic

Crystal class:  4/m -3 2/m

Twinning:  Common on {111}, generally repeated

Unit cell: a = 4.079 Ǻ

Colour:  Gold yellow; silver-white to orange-red from

Diaphaneity:

Luster:  Metallic

Habit:  Crystals octahedral, dodecahedral or cubic, flattened and elongated, dendritic; massive as nuggets, grains or scaled

Hardness:  2.5 to3

Specific gravity:  19.279

Cleavage:  None

Tenacity:  Hackly; malleable and ductile

Streak:  Same as colour

Synonyms/varieties:  Electrum (Ag-rich var.), Porpezite (Pd-rich var.), rhodite (Rh-rich var.).

Comments:  Series with silver