Unheated Tanzanite 1.83 (OVT183)

1.83 Carat
Multicolor Petrol
Light 33 to Medium 50
Free of Inclusions

GRADING REPORT OVT183

- Identification: Natural Unheated & Untreated Zoisite Tanzanite
- Carat: 1.83
- Shape: Oval
- Measures: 8.96x6.76x4.09 (millimeter)
- Color Grade: Very Good
- Tone: Light 33 to Medium 50
- Color Zoning: Mobile Visible
- Clarity: Free of Inclusions
- Cutting Grade: Very Good+
  > Brilliancy: 66%
  > Depth: 61%
- Origin: Tanzania
- Treatment: None

Certificate No: IGE D17191

Overall Grade: Very Good

Comment: Unheated 'petrol' tanzanite with more colors than fit on the lab report, but best imagined by the effect petroleum leaves on the surface of water, not only in colors but also equally shifting and moving. Most important to understand this gem is the very bright lilac center which throws a full blast of light back at the observer, overwhelming everything with luster (caught in its beginning in the close-up handshot below, indoors, no sunshine). Any attempt to focus into the table at exactly 90-degree results in a bright stroke of lightning, leaving only a washed-out blur not only for the camera but to an extent for the yes, too. One sees the gems radiating wildly but can't make out details let alone colors. Then, a slight move and the gem turns soft violet, then blue, another change and we have violet green, then purple violet, or blue green, then lilac violet... you got the idea. Most zoisite found in nature is brownish mauve turning deep blue under heat. Only a lucky few have naturally pleasant natural colors such as this (pink has been found, too). No inclusions, no window, no treatments. A never-get-bored gem in full ladies-size and a collector item. IGE report with 'no treatments'. IMO, such a gem with all its variations beats any what-ever block of boring same-same blue and costs only a fraction thereof.