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

Determining the geographic origin of yellow sapphires plays a critical role in the gem trade, as ori

Gem-quality sapphires containing ‘exotic’ elements such as Sn, Nb, Zr, Ta, W, are of special int

For many, fossiliferous tree resin, primarily amber, gained wide visibility to the public in 1993 wh