Tanzanite is a rare and beautiful gemstone that is prized for its unique blue-violet colour. It is a member of the zoisite mineral family and is found exclusively in the Merelani Hills of Tanzania, making it one of the world's most sought-after gemstones.
Tanzanite was first discovered in 1967 by a Masai tribesman named Manuel de Souza who was searching for sapphires. The discovery of the gemstone caused a sensation in the jewelry world, and it quickly became popular among collectors and enthusiasts. Tanzanite was named after its country of origin, Tanzania.
Tanzanite is a relatively soft gemstone with a hardness of 6.5 to 7 on the Mohs scale. It has a specific gravity of 3.35 to 3.55 and is typically found in small sizes. Tanzanite is also pleochroic, meaning it displays different colours when viewed from different angles.
Tanzanite is renowned for its unique blue-violet colour, which is caused by the presence of vanadium in the crystal structure. The gemstone can range in colour from light blue to deep violet, with the most valuable stones exhibiting a deep, rich blue hue.
Tanzanite is almost always heat-treated to enhance its colour. Heat treatment can improve the gemstone's colour by removing the brownish or yellowish tints that are often present in natural tanzanite. Less common but still possible is the presence of filler such as oil and/or resin to improve the gemstone's clarity.
Tanzanite is found exclusively in the Merelani Hills of Tanzania, making it one of the rarest gemstones in the world. The mining of tanzanite is tightly controlled by the Tanzanian government, and the supply of high-quality stones is limited.
Synthetic tanzanite is not produced, and if existing today it remain in the realm of research. However, it may be possible to pass off other blue gemstones as tanzanite's imitation, such as glass.
In addition to its beauty, tanzanite is said to possess metaphysical properties. It is believed to promote spiritual awareness and balance, and is associated with the throat and third-eye chakras. Tanzanite is also the birthstone for the month of December, and is sometimes given as a gift for 24th wedding anniversaries.