The more distinct the change of colour, the more valuable the stone. A fine alexandrite should show a vivid bluish-green in daylight and a purplish-red in artificial light, without any trace of undesirable brown or grey. If the origin of the stone is known beyond dispute to be Russia, we are talking about a real rarity of enormous value. Finely faceted alexandrites above one carat are thus among the most expensive gemstones in the world, rarer than fine ruby, sapphire or emerald.

 

To View the Color Chart of Corundum Stones,Please Click the following:

Corundum Stones Color Chart