Presents the four major groups of defects responsible for the color in nearly all yellow and orange diamonds.

Examines the effectiveness of hydrogen and oxygen isotopes in discriminating dolomite-related nephrites from the four most important occurrences worldwide.

A rough diamond crystal weighing 4.05 ct was observed with radiation staining on its surface.

Mineral and fluid phases within negative crystals in metamorphic sapphires provide us with general information on the sapphire and the trapped fluid itself.

Presents a study that suggests optically brightened pearls can be consistently separated from non-brightened pearls using fluorescence spectroscopy.

Gem silica, also known as “chrysocolla chalcedony,” is considered the most valuable variety of chalcedony.

了解 GIA 如何解决业界所担忧的问题，即未经披露的实验室制造钻石和花式米粒钻仿品与天然花式米粒钻混在一起。

对 GIA 专家而言，网络研讨会是一种轻松分享信息并与研究人员以及宝石和珠宝爱好者社区保持联系的非正式方式。

宝石学摄影记者 Robert Weldon（罗伯特·韦尔登）分享了他最喜欢的一些照片，并讲述了背后的故事。

This year at the AGTA show, the number of booths selling skillfully carved, fantasy cut, or expertly recut items was noticeably higher than in past years.

Orange crystal inclusion identified as the rare mineral triplite in a beryl from Pakistan.

GIA’s Hong Kong laboratory looks at a new radio-frequency identification (RFID) technology for tracking cultured pearls.

The unusual six-rayed trapiche pattern, identified mainly with Muzo emeralds, has also been discovered in Mogok sapphires and Mong Hsu rubies.

Investigates the chemical, physical, and gemological properties of attractive rhodonite-rich rocks from this Swiss deposit.

A nondestructive rapid screening technique uses fluorescence spectroscopy to identify treated colored pearls.

Untreated Russian emeralds, rarely seen in the market, demonstrate a range of color and degree of fineness.

Mina Stones promotes Nigerian gems including rubellite and sapphire as well as reviving traditional skills and symbols in the creation of original jewelry.

Application of slight pressure perpendicular to the twinning planes reveals the unusual property of this synthetic gem.