Shining light on “480 nm band” diamonds: Gemmological characteristics of an unusual group of diamonds with yellow and red luminescence
Marleen Bouman and Jelena Zarupski
Blue sapphire from Malacacheta of Minas Gerais, Brazil
Malacacheta, located in Minas Gerais, Brazil, is renowned for its alexandrite deposits and com-plex
Colored gemstones of metamorphic origin: Progress report in understanding how they crystallize at depth in East Africa, the Hindu Kush, Pamir Mountains, and the Middle-Urals Ring Structure
It is difficult to reconcile the existence of deposits of trans- parent gems of metamorphic origin w