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Ruby

Ruby is the most valuable variety of the corundum mineral species, which also includes sapphire.

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An area of a filled cavity in ruby exhibiting a lower luster than the ruby and surrounded by a granular texture, caused by a reaction layer of synthetic overgrowth. Reflected light (left) and brightfield illumination (right). Photomicrographs by Polthep Sakpanich; field of view 8.2 mm.

Ruby with Synthetic Overgrowth Lining Cavities

Sudarat Saeseaw, November 1, 2024

An unusual area of granular texture lining the cavity of a ruby indicates synthetic overgrowth.

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Figure 1. The 33.98 ct carved ruby cabochon from Mogok. Photo by Christopher Smith.

Arzakite Inclusion in Ruby from Mogok

Gaston Giuliani, Christopher P. Smith, and Julien Boulliung, November 1, 2024

A report on the first documented arzakite inclusion in a Mogok ruby.

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Figure 1. Strong angular graining in a Ramaura flux-grown synthetic ruby. Photomicrograph by Makoto Miura, field of view 3.99 mm.

Natural-Looking Inclusions in a Ramaura Synthetic Ruby

Makoto Miura, August 2, 2024

Milky clouds and flux inclusions in a synthetic ruby create a challenge for identification.

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Figure 1. This unheated 11.43 ct purplish red round ruby cabochon displayed a white twelve-rayed double-star phenomenon. Photo by Nuttapol Kitdee.

Fireworks in Ruby

Aprisara Semapongpan, August 2, 2024

An unheated purplish red ruby cabochon displays a white twelve-rayed double-star phenomenon.

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Figure 1. Colorless crystals with high relief in a ruby mined near Caraia in the Montepuez region. Photomicrograph by Wim Vertriest; field of view 3.6 mm.

Update on Inclusion Scenes in Mozambican Rubies

Wim Vertriest, May 3, 2024

GIA researchers identify zircon inclusions in several Mozambican ruby samples, potentially impacting origin determination criteria used for sources of East Africa ruby.

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Figure 1. Ten corundum samples from the Lofa River in Weasua, Liberia. Photo by Shunsuke Nagai.

Update on Liberian Ruby

Yuxiao Li, Yusuke Katsurada, Chie Murakami, and Mai Suzuki, May 3, 2024

Ten Liberian corundum samples are examined in GIA’s Tokyo laboratory.

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Rose channels in a 0.5 ct ruby. Photomicrograph by Aamir Sayed; field of view 0.75 mm.

Rose Channels in Ruby

Aamir Sayed, May 3, 2024

Examination of a pear-shaped ruby reveals hollow Rose channels.

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$Figure 1. An 8.57 ct heart-shaped fracture-filled ruby treated with a zinc glass filling. Photo by Adriana Robinson.$

Translucent Ruby Filled with Zinc Glass

Shiva Sohrabi and Amy Cooper, November 3, 2023

Examination of a heart-shaped ruby reveals a zinc glass filler.

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Figure 1. An unusual ruby with coloring reminiscent of a nebula found in the depths of outer space. Photo by Adriana Robinson.

“Nebula” Inclusion in Ruby Beryllium-Diffused to Heal Fractures

Michaela Damba, November 3, 2023

Fingerprints resulting from a flux-assisted heating process give a purple-red ruby a unique appearance.

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Figure 1. Greenland’s rubies are characterized by abundant twinning planes. The twinning planes are not altered by the treatment at a larger scale, but features associated with the twinning can be significantly affected by heating. Photo by S. Wongchacree; field of view 14.40 mm.

Characteristics of Treated Rubies from Greenland

Martin Viala, Wim Vertriest, Charuwan Khowpong, and Suwasan Wongchacree, August 4, 2023

An overview of the treatment process of ruby and pink sapphire from Greenland and its effect on inclusion scenes and chemistry.

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