Mineralpedia Details for Zoisite

Named after Sigmund Zois, Baron von Edelstein, a mineral enthusiast who determined Zoisite was a new mineral and contributed the first specimens. A widespread mineral, Zoisite is found in schists of medium grade that were regionally metamorphosed from rocks with high calcium contents. It is also found in eclogites and blueschist facies. Part of the Epidote Group, Zoisite is the only orthorhombic member.

Ref. Handbook of Mineralogy, Anthony et al (1995) and MSA at http://www.handbookofmineralogy.org/pdfs/zoisite.pdf

Formula

Ca₂Al₃(Si₂O₇)(SiO₄)O(OH) 

Crystal System

Orthorhombic 

Crystal Habit

Prismatic, Striated, Columnar 

Cleavage

Perfect, None, None 

Luster

Vitreous - Pearly 

Color

gray, apple green, brown, blue, rose red 

Streak

white 

Class

Orthorhombic - Dipyramidal 

Fracture

Even 

Hardness

6.5 

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A large, beautiful 88.7 carat, gemmy, naturally purple crystal. This specimen has not been heat treated. Some of these crystals are naturally baked by the sun through the geologic ages. This crystal in particular shows excellent color near the top and grades into a yellow-green at the base. The crystal is terminated and shows thin to thick platy forms like so many show and is vertically striated. Overall 3.5 x 2 x 1.3cm.

15 carat natural crystal, untreated, multiple faces on the termination. Overall 18x14x8mm.

Dirty white tabular crystals of Zoisite in matrix with Chalcopyrite.

Deep emerald grain, crystalline-granular Zoisite matrix with red ruby corundum veinlets and pods.

Apperantly this is a nice roadcoat. The Zoisite is the pink variety called thulite, which occur as elongated crystal slivers with white Armenite.

Granular pink Thulite. Acquired by Hampson in 1945.