Mineral type - Stichtite

Hydrotalcite Group


Name

Named after Robert Carl Sticht (Oct. 8, 1856 Hoboken, Hudson County, New Jersey, USA - Apr. 30, 1922 Launceston, Tasmania, Australia), formerly General Manager of the Mount Lyell Mining and Railway Company, Queenstown (Tasmania).

Physical Properties

Lustre: Waxy, Greasy, Pearly
Transparency: Transparent
Colour: Rose-pink to purple
Streak: White to light lilac
Hardness: 1½ - 2 on Mohs scale
Tenacity: Flexible
Cleavage: Perfect {0001}
Density: 2.16 g/cm3 (Measured) 2.11 g/cm3 (Calculated)

Chemical Properties

Formula: Mg6Cr3+2(OH)16[CO3] · 4H2O
Elements listed: C, Cr, H, Mg, O
Common Impurities: Fe

Crystallography

Crystal System: Trigonal
Class (H-M): 3m (3 2/m) - Hexagonal Scalenohedral
Space Group: R3m
Morphology: Massive. Matted or contorted aggregates of plates or fibers. Cross-fiber veinlets. Micaceous scales

Synonyms

Chrom-Brugnatellite

Varieties

Bouazzerite (of Cailleres)