Almost all amethyst (purple, pink and green) is heated to improve its appearance or deepen the color. It is February’s birthstone. Emerald is usually penetrated with oil, wax or resin to improve ...

GIA Colored Stone Identification and Origin Reports are available for ruby, sapphire, emerald, Paraíba tourmaline, red spinel and alexandrite. However, this does not mean GIA will be able to issue a ...

The system is capable of detecting 87 gemstones, providing gemologists, jewelers, and traders with a powerful tool for identifying and verifying various types of gemstones accurately.

Yanjun Song is from the College of Gemstone and Material Technology, Hebei GEO University in Shijiazhuang, China. Search GIA's library catalog of 65,000 books, 230,000 images, 2200 videos, 1200 ...