Provides criteria for detecting the resin filling of turquoise, an advanced treatment that reduces porosity and can dramatically improve appearance and stability.

A rare chatoyant effect is produced within play-of-color patches in a natural opal.

Presents a method for accurately predicting the color of a gem material when viewed in any direction as long as the polarized spectra and the viewing angle relative to the c-axis are known.

In a delightful juxtaposition, a diamond-shaped cloud inclusion appears in the center of a 0.53 ct round brilliant diamond.

The Carlsbad laboratory recently examined an unusually large faceted hexagonite with iridescent cleavage cracks and needle-like structures.

Two Australian rough diamonds demonstrate both pink and colorless sections in the same crystal.

The Carlsbad laboratory recently examined a Mexican opal containing a rare fluid inclusion with a freely moving gas bubble.

The author examined a 0.56 ct Fancy grayish bluish green diamond with prominent green radiation stains.

A graduate of GIA’s Hong Kong Jewelry Design program hopes her award-winning design will help raise environmental awareness.

Oblique fiber-optic illumination of thin-film fluid inclusions in Brazilian aquamarine reveals a kaleidoscopic play of interference colors.

Abnormal fluorescence supports the likelihood that this amber bracelet had been “baked” to enhance its color.

An overview of how the gem and jewelry trade, from miners to manufacturers, and from designers to dealers, dealt with the many challenges posed by the pandemic.

Attractive iridescence creates a beautiful “play-of-color” effect on dendritic healed fissures in a blue sapphire.

A beautiful new gem and mineral museum in Tucson is home to the stunning Somewhere in the Rainbow collection.

Two cabochons displaying white four-rayed “stars” are fashioned from one large natural diamond crystal.

Provides a visual guide to the internal features of natural, synthetic, and treated spinel, as well as inclusions of spinel in other gemstones.

A singly-terminated topaz from Pakistan hosts a prominent phlogopite crystal with strong dichroism and lamellar cleavage planes.

Presents the internal characteristics of natural P. maxima pearls, obtained from real-time microradiography (RTX) and X-ray computed microtomography (µ-CT) analysis of 774 samples.