What To Look For : The 5 C’s

In a similar way to buying diamonds, the Tanzanite Foundation grades tanzanite according to the FIVE C’s; Color, Clarity, Cut and Carat Weight. The higher the combination of these characteristics, the rarer and more valuable the tanzanite stone. Understand and check all 5 C’s before buying your tanzanite.

COLOR – Intensity of color and saturation of blue to violet

Color refers to the hue of the stone, and the degree of color saturation.

Tanzanite rarely appears to be pure blue, and almost always displays visible violet tones.

When graded by gemologists, a tanzanites color is always stated as a combination of blue and violet. A tanzanite which displays more than fifty percent blue in white light will be graded as “violetish Blue/vB “. Stones with a predominance of violet will receive the grade “blueish Violet/bV “.

The depth of color ranges from pale to deep hues. The deeper the color, the rarer the tanzanite. Larger stones are frequently darker and it unusual to find an intensely saturated stone under 5 carat’s in weight. There is no price difference between a vB or bV stone – however lighter stones are more commonly found than darker, more saturated stones which command a price premium. Tanzanite will appear more violet when viewed under yellow lighting.



CLARITY – Description of natural inclusions

Clarity refers to any natural flaws and inclusions in a tanzanite. Tanzanite ranges from Eye Clean, Slightly Included, Moderately Included to Heavily Included. The more flawless the tanzanite, the more valuable it is. Tanzanite which has eye visible inclusion (SI onwards) should trade at a discount.


CUT – Proportions and brilliance

Cut refers to a tanzanites brilliance, proportions and finish. An ‘Excellent’ cut ensures that the stone’s facets reflect light to create maximum brilliance. The more precise the craftsman’s cutting, the more valuable the tanzanite. Cut also refers to the shape of the stone.

CARAT – A weight measurement, equivalent to 1/5th of a gram

Carat Weight is the term used to measure a tanzanites weight. One carat has 100 points and weighs 1/5 of a gram. Two seemingly identical tanzanites will have different carat weights if they vary in depth.”Face up” measurements (lenght x width)  are the best way to gauge a tanzanites visual size.

CONFIDENCE – A responsible route to market

The 5th C is Confidence and is only applicable to tanzanite which is accompanied by the Mark Of Rarity Tag. The Mark of Rarity is the icon of the Tanzanite Foundation and is synonymous with Confidence. It is assurance that your tanzanite is authentic and has followed an ethical route to market. Learn more about the Mark Of Rarity.