Paraiba
Traditionally, blue and green tourmaline has been graded using standards borrowed from ruby, sapphire, and emerald. Darker-toned stones (seventy-five to eighty-five percent) have been the most sought after. 170 However,…
Traditionally, blue and green tourmaline has been graded using standards borrowed from ruby, sapphire, and emerald. Darker-toned stones (seventy-five to eighty-five percent) have been the most sought after. 170 However,…