and green colors. Photos by Masumi Saito. ABSTRACT Cuprian (copper-bearing) tourmaline, known as “Paraíba” tourmaline in the trade, has been an important gem since its discovery in 1989. Until now, ...

The much less abundant tenorite forms 20-30 µplaty grains. Electron microprobe analyses revealed that the tourmaline is cuprian elbaite (1 wt. % CuO), with significant contents of iron (2.7-3.1 wt. % ...