Below is the list of recognized holidays when GIA locations will be closed.View the holiday schedule for all GIA locations worldwide.

Fancy color diamonds are among the rarest and most valuable gemstones. Diamonds in the normal color range are colorless through light yellow and are described using the industry’s D-to-Z color-grading ...

Just over a century ago, in the summer of 1912, a workman’s pickaxe struck through the floor of an old tenement house in Cheapside, a commercial district near the renowned St. Paul’s Cathedral in ...

The GIA Gem Trade Laboratory (GTL) collected gemological data on 1,490 natural-color pink gem diamonds—both types I and II. While there was some overlap in gemological properties between the two ...

Aquamarine, Maxixe-type (irradiated) beryl, and two types of hydrothermally grown synthetic blue beryl currently available in the marketplace were investigated by classical gemological methods, ...

A set of six antique brooches, set with diamonds and light blue cabochons, was investigated with microscopy, Raman analysis, and EDXRF spectroscopy. Most of the cabochons proved to be fossilized ...

Figure 1. Six of the 13 cuprian liddicoatite tourmalines from this study. The faceted stones weigh 1.59–9.63 ct (average 3.95 ct). They are transparent and have greenish blue, green-blue, and green ...

Raman spectroscopy confirmed the identity of the material as pezzottaite by an intense peak at ~1100 cm –1, which is not present in beryl. Fourier-transform infrared spectroscopy showed features ...

Figure 1. Sapphires from Madagascar: a beautiful 3.29 ct untreated faceted stone and an assortment of rough in the background. Madagascar has produced many high-quality stones in the last few years ...

Figure 1. Glass in a silver brooch, hallmark from 1866. Private collection, photo by Jaroslav Hyršl. Tectites are members of a large group of impact glasses, formed by the collision of a meteorite on ...

CARLSBAD, Calif. – June 2, 2025 – Beginning later this year, GIA (the Gemological Institute of America) will start using descriptive terms to characterize the quality of laboratory-grown diamonds and ...

Diamonds are known for their hardness – their ability to resist scratches and abrasions. But diamonds are not impervious to damage, since their hardness is uneven along different crystal directions.