Shining light on “480 nm band” diamonds: Gemmological characteristics of an unusual group of diamonds with yellow and red luminescence

Over the past few years we have been seeing more and more lower quality stones in the lab. The reaso

Corundum, encompassing the highly prized ruby and sapphire varieties, stands as a cornerstone of the

In the accretionary Hellenides Orogen, gems occur in various rock types of mainly four tectonometamo