Tanzanite is a gemstone that is a member of the zoisite mineral group. It was first discovered in 1967 in the hills of Northern Tanzania. To date, this remains the only source of tanzanite..
As a gem that is pleochroic, tanzanite shows different colors depending on the viewing angle. This characteristic makes it unique and gives it a glowing appearance. In order to get the blue or violet-blue hue, most gem cutters orient the tanzanite gemstones. The vivid blue of the gem is also said to rival fine sapphire, making tanzanite a true, naturally beautiful gemstone.
Tanzanite ranges from ultramarine to sapphire blue in color. Under artificial light, it can also appear as more violet (especially when viewed from different angles). However, it is also found in the blue-violet combination and is best identified by its refractive index and density. In short, tanzanite exhibits perfect cleavage with an uneven fracture and is found in only one place on earth.
In most cases, tanzanite is heat-treated to enhance its blue and violet colors. The rough crystals show a large proportion of brownish yellow tints which vanish when put in high temperatures. This is also done to prevent mistaking the gem from other similar gemstones such as amethyst, iolite, sapphire and spinel.
The great hardness score makes tanzanite perfect for a variety of jewelry pieces. However, it should be worn with care because of its perfect cleavage (a single blow can cause it to split). Therefore, setting, polishing or cutting tanzanite gemstones should be a process where extra care is taken.
Today there are a variety of traditional and fancy faceted cuts used in tanzanite jewelry designs such as fantasy cuts. However, unfaceted tanzanite is also common and fashioned into beautiful jewelry such as bracelets, earrings and necklaces. The unique and vivid color makes tanzanite an excellent choice as a jewelry gemstone.