The Gem Testing Laboratory in Jaipur identified a black diamond-like specimen as boron carbide, a ceramic material typically used in nuclear, military, and aerospace applications.

An opaque carving was identified as color-coated corundum based on visual features, as RI and SG could not be measured because of the piece’s large size.

Examination of a 0.40 ct near-colorless round brilliant diamond with a large inclusion resembling a dumbbell

Observations made at GIA on 858 GE-processed diamonds revealed several interesting features that may be diagnostic of this kind of diamond. Specifically, a significant percentage exhibited a slightly hazy appearance, noticeable internal graining, and other unusual internal features.

This document provides the publication information for Gems & Gemology

This document provides the publication information for Gems & Gemology

This document provides the publication information for Gems & Gemology

This document provides the publication information for Gems & Gemology

This document provides the publication information for Gems & Gemology

This document provides the publication information for Gems & Gemology

This document provides the publication information for Gems & Gemology

This document provides the publication information for Gems & Gemology

This document provides the publication information for Gems & Gemology

Historically, natural black pearls have been one of the rarest and most exotic of gem materials.