Typomorphic features of tourmalines of the Malkhan pegmatite field from the Irkutyanka vein

In 2018 the Padparadscha engagement ring of Princess Eugenie (Figure 1), the niece of the king, gave

Fancy colour diamonds that derive their colour from nitro- gen-related defects (such as N3/N2 center

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