The gemstone tanzanite is naturally violet-blue in colour. One of the rarest gemstones, tanzanite can only be mined in Tanzania, one place in the world. Because of its rarity and vivid blue colour, tanzanite is prized. According to western astrology, tanzanite is the birthstone for December. In recent years, thousands of people have chosen Tanzanite for their engagement ring. The colour tone and saturation, transparency, and lustre of tanzanite all affect its price. Because of its scarcity and high demand, tanzanite is regarded as the best gemstone for investment.