A RANGE OF COLORS
Tanzanite forms in a wide range of colors: from light sky blues and lilacs through to deep indigos and royal blue. Some large tanzanites appear to be pure blue, but in most cases, a closer look will show both colors simultaneously.
PLEOCHRISM: ONE STONE, TWO COLORS
Due to its unique crystalline structure, tanzanite is one of only two known gemstones that clearly exhibits two colors at once. This characteristic (called pleochrism) means a tanzanite can never be pure blue or pure violet color, but rather, always a combination of the two. Rock any tanzanite back and forth – and you will see both colors as the angle of the stone changes.
Occasionally, very large tanzanites display an intense violetish and blue, with flashes of a third color: burgundy.
- A tanzanite which has more violet than blue is described as “bluish-Violet” or “bV”
- A blue dominant tanzanite, which reflects more blue than violet, is described as “violetish – Blue” or “vB”
- Tanzanites with deep and highly saturated hue are the rarest and most expensive, while pastel and lighter colored stones are more common.
- The darkest colors are usually seen in larger sized stones, above 5 carats; however, a large stone with less saturation will have lower value.
- Smaller tanzanites are usually more lightly colored. It is unusual to find a deeply colored stone in a smaller size.
- Each tanzanite, no matter its color, is still incredibly rare. Remember that a deep violetish blue tanzanite does not necessarily mean that the stone is better: just that it’s rarer.