Tanzanite

Nearly all Tanzanite on the market undergoes heat treatment: the rough stone mined from the hills of Merelani is naturally brown or reddish in color, and it’s a controlled heating process that reveals the intense blue-violet hue we know. This isn’t a deception — it’s a standard practice, recognized and disclosed throughout the industry for decades, just as it is for most blue sapphires on the market.

This treatment does not alter the stone’s crystal structure in any way, nor does it reduce its value or durability over time: it is an integral part of the finishing process, just like polishing or cutting. The extremely rare, never-heated natural Tanzanites, with their more subtle color, remain highly sought after by collectors and can command even higher prices precisely because of their exceptional rarity.