Tanzanite is a trichroic mineral with three shades of color. Its name is derived from Tanzania, where it was first discovered. The gemstone’s color comes from the different chemical compositions of its constituent crystals and the presence of vanadium and chromium. Tanzanite generally has a blue to violet hue but can be greenish in some rare specimens.
The refractive index can be as high as 1.932, higher than any other known gemstone. The stone is also notable for its strong trichroism, even in small rough pieces. The mineral’s three colors are caused mainly by different wavelengths of light reflected by the tiny crystal blades composed of the gem. Different colors of light are typically reflected at different angles.
Interesting facts about Tanzanite’s unusual coloring
◊ The blue color of Tanzanite is produced by the simultaneous reflection of light from all wavelengths. It is due to the presence of specific chemical impurities within the gemstone. The gem contains tiny rod-like crystals called silicate lamellae arranged in triangular groups along with its crystal structure, which is hexagonal and close-packed. Each group has a side length different from any other group, which gives rise to an optical phenomenon known as dispersion. This property is also in diamonds, but to a lesser degree than in Tanzanite.
◊ The green color of Tanzanite is due to the absorption of darker blue and violet wavelengths by the presence of chromium impurities. It leaves a yellowish-green hue to the dark portions of the mineral’s display.
◊ The red color is the rarest, caused by vanadium impurities that give rise to iridescent effects. These are most brightly visible when Tanzanite is placed in an area with too much fluorescent lighting.
◊ Color zoning is the variation in color from one part of the stone to another. This phenomenon can be observed among different pocket samples and within the same piece of rough. Zoning is due to differential staining of crystal portions during formation and can be very prominent or barely noticeable.
Uses of Tanzanite
◊ Tanzanite is used in jewelry for its attractive blue-violet color.
◊ Geologists can use Tanzanite to identify the components of fossilized rocks and for dating purposes. It is possible to figure out the age of a rock by studying its chemical composition, which is dependent on how long it took for the rock to cool from a molten state. Color change in Tanzanite can also be used as a helpful indicator.
◊ The gem has many industrial applications. Its hardness allows it to be used as a heat-resistant material, and its heat capacity makes it an excellent coolant for infrared lasers. It can also be used as a substitute for sapphire in high-power applications that generate very high temperatures.
Benefits of Tanzanite and the importance of its properties
◊ Tanzanite is one of the hardest minerals on earth, second only to diamond. Its hardness allows it to be used in jewelry, despite its rarity.
◊ The gemstone’s color makes Tanzanite a rare gem that is highly prized. It has become popular among gem collectors whenever specimens are found. It is especially true since the value of tanzanite gems has not been influenced by diamonds or other colored gems that have become more available recently.
◊ Tanzanite is not known to cause significant health problems and does not cause cell damage or harm to the human body. However, the gem does have adverse effects on plant life due to its related mineralization and precipitation of ferns and cataphylls plant growth.
◊ Despite its impressive appearance, counterfeiting does not affect the gem’s price. It is because Tanzanite has a very complex composition which makes reproducing it in any other material difficult. In many cases, faking Tanzanite requires a multimillion-dollar effort, opposite to rare cases of forgery of other gems.
◊ The gem is not very sensitive to high temperatures, pressure, or another physical injury that would damage most gemstones. It makes Tanzanite an ideal choice for jewelry placed near the human body.
Tanzanite is known for its beautiful blue-violet color and rare properties. It makes a fine choice for jewelry, especially when placed close to the human body. As a result of its hardness and capability to undergo processing at high temperatures, Tanzanite can also be used industrially. The mineral is often used to manufacture other gemstones, such as sapphires, and in high-power laser applications.