Tanzanite pair 2.54 cts

Tanzanite is strongly trichroic, meaning it transmits three distinct colours — blue, violet, and burgundy — along its three optical axes. Depending on the cut orientation and the quality of the light source, a single stone can appear more sapphire-blue under daylight or more violet under incandescent light. This colour-shift quality is one of the defining characteristics collectors assess when evaluating a fine tanzanite.

Tanzanite rates 6 to 7 on the Mohs hardness scale and has distinct cleavage in one direction, making it more vulnerable to impact than sapphire or diamond. It should never be cleaned in ultrasonic or steam cleaners, as vibration and heat can cause fracturing along cleavage planes. For daily wear pieces, a protective bezel or recessed setting is advisable; soft cloth cleaning with lukewarm water and mild soap is always the safest routine.

With only one known deposit in the world and mine output declining steadily, tanzanite’s long-term scarcity argument is well-founded among informed collectors. The most critical value drivers are colour saturation — specifically a deeply saturated, even blue-violet without grey masking — followed by clarity, cut quality, and carat weight. Matched pairs command a premium above individual stones of equivalent weight because the additional labour and rough required to produce them significantly reduces their supply.

For stones of collector or investment grade, independent laboratory certification provides an objective record of weight, colour grade, treatment status, and origin that protects value at resale. The Gübelin Gem Lab and SSEF in Switzerland are widely regarded as the most authoritative for coloured stones, while GIA certification is broadly recognised across international markets. For a matched pair, individual certificates for each stone are preferable, as they document the independent assessment of each gem’s characteristics.