本系列第 4 部分（共 5 部分）：有色宝石（非钻石）的价值因素、设计和切工品质。本文深入分析了切磨师的各种选择，并探讨了业内用于评估相对价值的其他因素。

Over the last decade, the production methods used to create synthetic diamond melee have improved substantially, along with the quality of the specimens themselves.

Aesthetically pleasing inclusions are found in topaz from Pakistan’s Shigar Valley.

A look at the color zoning exhibited by the largest HPHT-treated blue diamond graded by GIA.

For the first time, wurtzite is found as an inclusion in gem material.

Lotus Gemology receives submissions of star stones on a regular basis, so when we first saw the specimen shown here, it appeared to be one among many of our usual stones to test.

Crassostrea virginica, the so-called Eastern or American oyster, is a commercial seafood widely distributed along the east coast of the United States to the Gulf of Mexico.

A black star sapphire produced from eastern Thailand, showing both golden and silver rays, is studied at GIA’s Bangkok lab.

An unusual assembled stone is examined at GIA’s New York lab.

Projects developed by the GemHub to benefit miners, cutters, and others involved in the gem and jewelry industry.