The name "tanzanite" was given because the world's only known tanzanite deposit of commercial importance is in northern Tanzania. The name reflects the gem’s limited geographic origin. The mines are all located in an area of about eight square miles in the Merelani Hills, near the base of Mount Kilimanjaro and the city of Arusha. Tanzanite is exceptionally brilliant, and is unique among gemstones for it's multi-dimensional color. In gemological terms, tanzanite is trichroic, which means that when brought out of the earth, its crystals radiate three different colors, blue, violet and burgundy. Once cut and polished, tanzanite becomes a dazzling kaleidoscope of royal blue, indigo and periwinkle. There is a wide and varied range of hues, from flattering light blues and lilacs to deep, dark blues and violets. Larger stones tend to exhibit the most intense colors and the most brilliance and fire, and the darker colors typically command the highest prices. Matching pairs are greatly sought after due to the rarity of finding two stones of identical color.