Research Article Search Results

Figure 1. The vivid colors seen in fine gem-quality spinel are derived from the mixing between multiple different chromophores in a range of ratios and concentrations, as in this fine 13.52 ct violetish purple spinel. Courtesy of the Dr. Edward J. Gübelin Collection. Photo by Robert Weldon/GIA.

A selection of 74 non-bead cultured and 12 bead cultured pearls grown in cultured pearl sacs and harvested directly from operated mollusks were collected and their internal structures examined using real-time microradiography and X-ray computed microtomography analyses.

Extensive analysis of early beads and pendants from archaeological sites in the French islands of the Lesser Antilles identified the objects as sudoite, which has never before been documented in any lapidary production.

The Carlsbad laboratory recently had the chance to examine a 4.60 ct cushion-cut zircon with truly unusual color behavior.

This study examines FTIR spectra of yellow sapphire heat treated in an oxidizing atmosphere to deepen its color.

Four pearls submitted to the Bangkok lab proved to be natural non-nacreous specimens dyed pink, apparently to imitate true conch pearls.

An overview of the Fall 2021 Gems & Gemology content.

Several shells received at the Hong Kong laboratory were identified as fossils replaced by emerald crystals.

A fixed star indicating manufactured asterism helps to identify an imitation star sapphire.

Accidental laser damage likely caused unusual internal spiral markings in a 2.44 ct CVD-grown diamond.

Fura Gems hosted its first sales event for rough Mozambican rubies in August and September 2021.

Using customized, image-based measurement systems to quantify the effect of fluorescence on the color, brightness, and transparency of gem diamonds viewed in both face-up and table-down orientations.