Spectroscopic Characteristics of Low-Temperature Heated Blue to Violet Spinel
Although spinel is rarely treated, there have been some heated spinels available in the trade.
James Shigley Receives Robert M. Shipley Award
Distinguished research fellow Dr. James Shigley receives the Robert M. Shipley Award for his contribution to the science of gemology.
Willemite in Topaz
A colorless topaz from Nigeria hosts the only known example of willemite as an inclusion in topaz.
A Unique Double Cat’s-Eye Emerald
The Tokyo lab examined a stunning double cat’s-eye emerald whose chatoyancy was created both by its cut and its inclusions.
New CVD Material Submitted for Analysis (英语)
A group of large, high-quality CVD material demonstrates the continued challenge of identifying laboratory-grown gems.
Faceted Octahedral Diamond with Octahedral-Shaped Inclusion
Creative faceting highlights an octahedral-shaped cloud inclusion in a 2.01 ct diamond octahedron.
Zircon with Unusual Color-Change Behavior
The Carlsbad laboratory recently had the chance to examine a 4.60 ct cushion-cut zircon with truly unusual color behavior.
Laboratory-Grown Diamond with Internal Laser Markings
HPHT-Processed Diamond with Counterfeit GIA Inscription
Careful comparison of two GIA reports reveals a fraudulent inscription on a laboratory-produced diamond presented as a natural.
Hematite “Rose” Inclusion in Aquamarine
Recently, a 23.67 ct pear cabochon aquamarine with light greenish blue color and poor clarity was sent to the Taiwan Union Lab of Gem Research (TULAB) for identification.
Glass Imitation of Star Sapphire
Heat Treatment Effects on the Behavior of the 3161 cm–1 Feature in Low-Iron Metamorphic Yellow Sapphire
This study examines FTIR spectra of yellow sapphire heat treated in an oxidizing atmosphere to deepen its color.
Fura Gems’ Inaugural Ruby Sale
Fura Gems hosted its first sales event for rough Mozambican rubies in August and September 2021.
FTIR Observation on Sapphires Treated with Heat and Pressure
A study on heat with pressure treatment of blue sapphires reveals FTIR patterns associated with different iron concentrations.
Fossilized Shell Consisting of Emerald
Persian Turquoise: The Ancient Treasure of Neyshabur
Reports on the geology, background, and current state of mining and production at Iran’s largest turquoise mine.
Purple Gem Spinel from Vietnam and Afghanistan: Comparison of Trace Element Chemistry, Cause of Color, and Inclusions
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.
Internal Structures of Known Pinctada maxima Pearls: Cultured Pearls from Operated Marine Mollusks
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.

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