Tanzanite is a rich blue-violet stone, discovered in the 1960's in the foothills of Mount Kilimanjaro.
A member of the Zoisite family of gemstones, this beautiful blue-violet stone is mined only in Tanzania and is often mistaken for a sapphire. Tanzanite is strongly 'pleochroic', which means this gemstone displays different colours - red, violet, blue, grey - when viewed from different angles. The blues appear more evident when subjected to fluorescent light and the violet hues can be seen readily when viewed under incandescent illumination.
With a hardness rating of 6.5 tanzanite is somewhat soft and fragile - most are set in earrings or pendants and care should be taken with tanzanite rings.
In its natural form, tanzanite is typically a brown colour, however most blue tanzanites for sale today owe their colour to heat treatment, which is what reveals its attractive pleochroic blues and violets. Simply richer in colour, heat-treated tanzanite is considered to be the same quality as non heat-treated tanzanite's, and as a rule, the larger the tanzanite, the deeper the colour.
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.
www.catherinebuddjewellery.co.uk
