◂ BACK TO GEM ENCYCLOPEDIA
Spinel
The Black Prince's Ruby. The Timur Ruby. For centuries, spinel, the great imposter, masqueraded as ruby in Europe's crown jewels.
See Gem As
Tools
Research
Etch Marks, Negative Crystals, and Etch Tubes in Spinel from Madagascar
A spinel from Madagascar, mixed in with a parcel of blue sapphire, exhibited an array of internal features.
The Elahera Gem Field in Central Sri Lanka
The Elahera gem field currently provides approximately 35% of the gemstones exported from Sri Lanka.
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.
Fissure with Moiré Pattern in Spinel
A precipitation of an unidentified mineral creates a complex moiré pattern in a fissure of a purple spinel.
Color Modification of Spinel by Nickel (Ni) Diffusion: A New Treatment in the Gem Market
GIA researchers report on a new nickel-diffusion treatment used to modify color in spinel and present criteria for identification.
Color Mechanism and Spectroscopic Thermal Variation of Pink Spinel Reportedly from Kuh-i-Lal, Tajikistan
A detailed spectroscopic investigation of the color of pink spinel reportedly from the Kuh-i-Lal deposit in the Pamir Mountains of Tajikistan.
Micro-Features of Spinel
Provides a visual guide to the internal features of natural, synthetic, and treated spinel, as well as inclusions of spinel in other gemstones.
Field Gemology: Building a Research Collection and Understanding the Development of Gem Deposits
With more than 90 field expeditions on six continents since 2008, GIA has accumulated over 22,000 colored stone reference samples. This extensive collection of colored stones with known origins supports GIA’s research on geographic origin determination.
Gemstones in the Era of the Taj Mahal and the Mughals
A look at the gem ornamentation of this landmark, as well as the jewels of the Mughal dynasty.
Star Spinel with Four and Six Rays
Lotus Gemology receives submissions of star stones on a regular basis, so when we first saw the specimen shown here, it appeared to be one among many of our usual stones to test.
Quarterly Crystal: Wurtzite Phantom in Quartz
For the first time, wurtzite is found as an inclusion in gem material.
