Gemological Characterization of Montana Sapphire from the Secondary Deposits at Rock Creek, Missouri River, and Dry Cottonwood Creek
Examines the mining history and geological characteristics of the three secondary sapphire deposits in the state of Montana, as well as the properties of these sapphires (unheated and heat-treated).
“Atypical Beads”: Variations of Two Types of Nuclei
Four atypical bead cultured pearls with variations on two types of nuclei are examined in the Mumbai laboratory.
HPHT-Grown Colorless Diamond Displaying Unusual Phosphorescence Effects
Study of phosphorescence produced from visible light suggests future difficulty in accurately assessing bodycolor of HPHT-grown diamonds.
A Gastropod Shell in a Unique Shell Blister
GIA’s Mumbai laboratory encounters a unique example of a shell blister encompassing a gastropod shell.
Color Study of Fancy Sapphire from Greenland
The Bangkok laboratory identifies the chromophores responsible for the fancy colors observed in treated sapphire from Aappaluttoq, Greenland.
Bright Orange Sapphire from Greenland
A transparent bright orange sapphire from Greenland stands out at the AGTA show in Tucson.
Morphology of Colombian Emerald: Some Less-Common Cases and Their Growth and Dissolution History
Evaluates the growth mechanisms of special morphological features in Colombian emerald, including possible relationships to trapiche emeralds and samples displaying the gota de aceite effect.
Starry Night in Diamond
Cloud inclusions resembling stars at night are observed in a faceted diamond.
Spring 2023 G&G Publication Information
This document provides the publication information for Gems & Gemology
Treated Freshwater Non-Bead Cultured Pearls with an Antique Appearance
GIA’s Mumbai laboratory examines 12 freshwater pearls showing signs of aging.
New Violet Orbicular Chalcedony from Ethiopia
Tumble-polished freeforms of violet chalcedony with orb-like structures from a new find in Ethiopia were on display at GJX.
Apatite in Hackmanite
A dramatic color change is observed in a hackmanite sample with an apatite inclusion.
Arrow-Patterned Negative Crystals in Sapphire
Examination of a sapphire reveals negative crystals arrayed in an arrow-like pattern.
Inclusions in Chondrodite
Various inclusion types are observed in a bright orangy yellow chondrodite.
Three-Phase Inclusion in Alexandrite
Examination of alexandrite reveals three phases of matter within a single inclusion suite.
Unusual Solid Inclusions in Flame-Fusion Ruby
Numerous natural-looking dark red solid inclusions are observed in a flame-fusion laboratory-grown ruby.
Xenomorphic Garnet in Diamond
A purplish pink garnet crystal formed in the same octahedral shape as its diamond host.
GIA Museum’s “Paint the Town Ruby Red” Exhibit at TGMS
The GIA Museum’s exhibit at TGMS spotlights a Burmese ruby necklace to illustrate the role of chromium in fluorescence.