Trichroic Gemstones - Tanzanite and Iolite
Pleochroism means “more colours.” Pleochroic gems show two or three colours when viewed from different angles. Trichroic gems show three colours. Tanzanite & Iolite are examples of a trichroic gems.
Tanzanite – Moh’s Scale Hardness 6-7 (glass is 7)
Tanzanite was only discovered in 1967. It has a striking blue/violet colour although there is a 3rd colour of yellow/brown. It is cut to produce the blue/violet through the top table facets. Tanzanite is uniquely trichroic and has since become the second most popular blue gem after sapphire. The name "tanzanite" was given because the world's only known tanzanite deposit of commercial importance is in northern Tanzania.