Zoisite Gemstones

  • Hardness

    6.5 on the Mohs scale.

  • Occurrence

    Zoisite occurs in Tanzania (tanzanite) and Kenya, Norway, Austria, Western Australia, Italy, USA (North Carolina)

  • Appearance

    Opaque, green with black streaks. Often found included with opaque ruby (corundum). Transparent green zoisite is heat treated to form violet/blue tanzanite.

  • Enhancements

    Green zoisite is not enhanced. Purplish-blue is usually heat-treated.

    More information on gemstone enhancements.

  • Heat Treatment

    Violet-Blue Tanzanite is the result of heat-treatment, as the following photo illustrates:

    Rough Zoisite

Zoisite Varieties
Zoisite Varieties

Zoisite
Zoisite

ZOI131
ZOI131
36.04 ct.
30.0x20.5mm Cabochon, Pear Cut
Medium
Strong Very Slightly Bluish Green
Opaque
[N] Not enhanced.
One of a kind.
With areas of Reddish and Black.
Zoisite

Calibrated Zoisite
Calibrated Zoisite

Specify size, shape and quality when ordering. Prices are subject to change without notice. Actual carat weight may vary from the average carat weight listed.

  • A Zoisite with ruby. Opaque, good cut, good polish.

Zoisite Quality A
Shape Size Avg. Weight Price Each
25x18mm
~
30x22mm
~
40x30mm
~