What You Need to Know About Tanzanite
Only from the Merelani Hills in Tanzania comes Tanzanite — one of the most unique gemstones discovered in the past century. According to historical accounts, Maasai herdsmen discovered the gem in 1979 after bush fires altered the brownish colour of the mineral zoisite into a striking violet-blue.
After severe flooding in 1998, the South African company AFGEM gained control over most of the mining area. With the only known source secured, Tanzanite was introduced to the global jewellery market and rapidly became a sought-after gemstone. Due to its rarity and controlled supply, Tanzanite values have increased steadily, with demand continuing to influence pricing.
Colour (Hue)
Tanzanite colour is described as violetish-blue (vB) when blue dominates, or bluish-violet (bV) when violet is dominant. Saturation ranges from poor to vivid. Under incandescent lighting the violet component becomes more pronounced, while fluorescent light enhances the blue component. This colour shift is a defining and fascinating characteristic of the gemstone.
Smaller Tanzanite gems generally appear lighter in colour, while larger gemstones display deeper, more intense saturation.
Hardness
Tanzanite has a hardness comparable to emerald and must be handled with care. For this reason, it is ideally suited to jewellery such as pendants, earrings, and brooches, rather than rings intended for daily wear.
Clarity
Tanzanite clarity is typically very good, and large gemstones are often found to be eye-clean, making them especially attractive for fine jewellery.
Cut
Cut quality plays a vital role in Tanzanite’s beauty. Well-proportioned gemstones return more light to the eye, enhancing brilliance and colour, while poorly cut gems appear dull regardless of size.
Weight
Tanzanite weight is measured in carats, where one carat equals 200 milligrams — the same system used for diamonds.
Value and Treatment
Tanzanite value increases with stronger colour saturation and larger size. As with many gemstones, Tanzanite is routinely heat-treated to enhance its colour. This treatment is accepted within the trade and should always be disclosed.
Beware of Imitations
Modern manufacturing techniques have produced convincing look-alikes. Always request a certificate and written guarantee issued by a qualified gemmologist when purchasing Tanzanite to ensure authenticity and value.
Visit Prins & Prins Diamonds for professional gemstone advice, certification, and expert guidance when selecting Tanzanite jewellery.