Marquise Shaped Tanzanite Gemstone ranges from ultra mine to a light purplish blue colour. Shree Prakash Gems manufactures Marquise Shaped Tanzanite Gemstone. Shree Prakash Gems also manufactures wide range of Tanzanite gems in different shapes. Marquise Shaped Tanzanite Gemstone is in fact a blue variety of zoisite gemstone. The hydrated calcium aluminium silicate miner achieves only hardness 6.5 to 7 on the Moh`s scale, and is thus not very resistant. It is a very special and unique gemstone. The Gem is available in trichroic colour and it shows different colours when viewed in different directions. It should be worn with care, never be cleaned by ultrasonic method and never come into contact with acids.