An overview of the Winter 2025 Gems & Gemology content.

GIAは2026年1月1日、デザインを一新したカラーストーンレポートと新サービスを開始します。

GIA will launch redesigned colored stones reports and new services on January 1, 2026.

A diamond octahedron from South Africa hosts a rare yellow-orange almandine-pyrope garnet crystal.

Organic-rich material is observed through an opening in a hollow natural pearl.

A study analyzing the thermal behavior of the 3161 cm^–1 IR feature in 10 natural corundum samples from various deposits.

A euhedral prismatic pargasite crystal is identified in pink spinel.

Natural pearl cores are used to simulate the appearance of natural pearl growth in two assembled pearls mounted in a pair of earrings.

A diamond ring from a claw game in Japan is analyzed.

Examination of a 1.34 ct ruby reveals a unique inclusion formed during heat treatment.

The Carlsbad lab receives a laboratory-grown colorless sapphire with weblike fractures containing concentrations of dye.

A combination of growth and dissolution features contribute to a yellow diamond’s unique shape.

A 63.17 ct dumortierite rough crystal is examined in the Bangkok laboratory.

Blue needle-like inclusions are analyzed in three quartz spheres.

Gersdorffite inclusions in quartz exhibit either triangular or hexagonal shapes when viewed from different directions.

A non-nacreous pearl with a netted surface resembles the exterior of a melon.

An eight-rayed star peridot with a star system made up of two different sets of inclusions is described for the first time.

A 2.50 ct natural type IIa/IaB diamond submitted to the Dubai laboratory shifts to type IIb after deep-UV excitation.

Play-of-color pattern in Ethiopian opal is reminiscent of a turtle’s shell.