Jewellers of Birmingham - Diamond Engagement Ring and Wedding Ring Specialists

Tanzanite - December birthstone

Mohs Hardness  6 to 7

Mined From  Tanzania

Species    Zoisite

Typical Cutting Style   Faceted

Colour   light to dark violet blue and bluish purple as well as pure blue. Rich, deep hues are valued most, but you will usually see these in larger stones ( 5ct upwards). Tanzanite typically shows strong pleochroism, which means it displays different colours from different directions it usually looks violet-blue from some directions and purplish from others.

Predominately blue tanzanite is generally worth more per carat, paler tones are more affordable.

Chemistry  Ca2 Al3 (SiO4)3 (OH) Calcium aluminium silicate.

Treatment  Tanzanite are routinely heat treated to produce the blue purple colour.

Inclusions  Tanzanite gemstones are often inclusion free. Eye visible inclusions decrease the value of tanzanite especially in the lighter coloured stones.

Cleaning & Care  Warm soapy water and a soft toothbrush will help maintain the sparkle of your Tanzanite. Ultrasonic and steam cleaners are  never recommended for tanzanite. Tanzanite is stable under normal wearing conditions, which means it is resistant to the effects of heat, light, and common chemicals. Even so, tanzanite should not be subjected to very high temperatures or sudden temperature changes. It can be attacked by exposure to hydrochloric and hydrofluoric acids. Tanzanite is a special-care gem for two reasons: sensitivity to thermal shock and potential for cleavage. Sometimes the temperature change from very hot to cold can be enough to develop cleavages in tanzanite. Visit us on a yearly basis for a FREE clean and polish service.

Storing Your Tanzanite  When you are not wearing your tanzanite jewellery place it in a cloth pouch or in a separate compartment to other gemstone jewellery (i.e, diamonds are a higher hardness level on the Mohs scale) they could cause scratches to other items of gemstone jewellery that have a lower hardness level.

Interesting Facts  Tanzanite is a relatively new gemstone, it was first found in 1962, scattered on the Earths surface in northern Tanzania

Tiffany and Company recognised the stones potential as an international seller and made a deal to become its main distributor. Tiffany named the gem after the country it came from, and promoted it with a big publicity campaign in 1968.

Probably the most noteworthy tanzanite gemstone is the Queen of Kilimanjaro, which is set into a white gold tiara along with 803 garnets and 913 diamonds. It is thought to be one of the world's largest faceted tanzanite gemstones, and weighs 242 carats.

In the early 2000s the American Gem Trade Association choose Tanzanite as a December birthstone, the first change to their birthstone list since 1912