Sjögrenite

Formula: Mg₆Fe₂(CO₃)(OH)₁₆.4H₂O

Origin of name: for H. Sjögren, Swedish mineralogist

Crystal system: hexagonal

Crystal class: 6/m 2/m 2/m

Twinning:

Unit cell: 

Colour: white, yellowish, brownish

Diaphaneity: transparent

Luster: vitreous to waxy, pearly on cleavage

Habit: thin hexagonal plates

Hardness: 2.5

Specific gravity: 2.11

Cleavage: 1; {0001} perfect

Tenacity: 

Streak: 

Synonyms/varieties: member of the hydrotalcite group, dimorphous with pyroaurite

Comments: