Amethyst may develop into the more common citrine and rarer green quartz naturally under certain geologic conditions. On the California-Nevada border, just north of Reno, amethyst, citrine, and green ...

Two Antique Mughal Spectacles with Gemstone Lenses Unique diamond and emerald-lensed spectacles from the Mughal Empire were tested in GIA’s New York laboratory. Read More ...

完整的 4C 评估，并附有净度特征标绘图。实验室培育钻石的腰围上会用镭射刻字技术刻上“Laboratory-Grown”（实验室培育）字样和 GIA 报告编号。适用于颜色为 D 到 Z 级、重 0.15 克拉或以上的未 ...

Copper-bearing tourmaline from Mozambique was first recovered in 2001, but its Cu content was not recognized until 2003, and it was not widely sold with its Mozambique origin disclosed until 2005. It ...