Two pearls presented a unique challenge, as testing at three different gemological laboratories could not conclusively identify them as natural or cultured, determine a freshwater or saltwater growth environment, or specify the producing mollusk.

Provides a visual guide to the internal features of natural, treated, synthetic, and imitation opal.

Blue diffusion-treated sapphires are becoming more prevalent than ever before.

Large blue and pink diamonds were among the top lots of the fall auction season, including the most expensive auction jewel of 2023.