Pyroaurite

Formula: Mg₆Fe₂(CO₃)(OH)₁₆.4H₂O

Origin of name: from Greek pyr = fire and Latin aurum for gold

Crystal system: hexagonal

Crystal class: -3 2/m

Twinning: 

Unit cell: 

Colour: yellowish white, brownish white, silvery white, greenish, colourless

Diaphaneity: transparent

Luster: vitreous to waxy, pearly

Habit: crystals thin to thick tabular, fibrous

Hardness: 2.5

Specific gravity: 2.12

Cleavage: 1; {0001} perfect

Tenacity: 

Streak: 

Synonyms/varieties:

Comments: dimorphous with sjögrenite, member of the hydrotalcite family