Natural Ruby Inclusions

Explore ruby inclusions in Hyperion, the Lotus Gemology inclusion database. Hyperion contains photomicrographs of inclusions and internal features in natural ruby, documented with information on geographic origin, treatment, lighting conditions, field of view, photographer and published references.

Rutile silk (high relief) with daughter crystals (lower relief) at the broad ends is a common feature of Mozambique rubies. Heat treatment often produces a breakdown, creating white spots or bubbles within the daughter crystals, as can be seen here.
Rutile silk (high relief) with daughter crystals (lower relief) at the broad ends is a common feature of Mozambique rubies. Heat treatment often produces a breakdown, creating white spots or bubbles within the daughter crystals, as can be seen here.
Rutile silk (high relief) with daughter crystals (lower relief) at the broad ends is a common feature of Mozambique rubies. Heat treatment often produces a breakdown, creating white spots or bubbles within the daughter crystals.
A large gas bubble trapped within the glass filling a large cavity of this treated Mozambique ruby. Flux-healed fingerprints can also be seen nearby.
Flattened gas bubbles within a glass-filled fissure of a treated Mozambique ruby.
Rubies from Myanmar’s Mong Hsu region only rarely feature rutile silk. Instead, the silk-like exsolved particles are composed tiny particles of the mineral diaspore—α-AlO(OH). Diaspore gets its name from the Greek word “to scatter,” in allusion to its propensity to decrepitate (audibly pop) when heated. Diaspore silk is extremely heat sensitive and its alteration can help identify heat treatment.
Mong Hsu rubies are generally heat treated to remove the blue cores that darken their color. In addition, most contain open fissures that disfigure the gems. Treaters use fluxes like borax to heal the fissures with microscopic amounts of synthetic ruby, which recrystallizes in the cracks. This photo shows a flux-healed fissure, accompanied by a cottony cloud of diaspore silk.
Rubies from Myanmar’s Mong Hsu region only rarely feature rutile silk. Instead, the silk-like exsolved particles are composed tiny particles of the mineral diaspore—α-AlO(OH). Diaspore gets its name from the Greek word “to scatter,” in allusion to its propensity to decrepitate (audibly pop) when heated. Diaspore silk is extremely heat sensitive and its alteration can help identify heat treatment.
Undissolved rutile silk with attached daughter crystals in the basal plane of a ruby from Mozambique’s Montepuez region.
Inclusions of what is probably pargasite with dark grains of embedded chromite in a ruby from Montepuez, Mozambique.
Probably the most common inclusion in Mozambique ruby is rutile silk. The rutile forms as high-relief twinned needles with tiny re-entrant angles at the broad end, attached to “daughter” crystals of lower relief. During heat treatment, the daughter crystals may show breakdown in the form of bubbles or mottling.
Probably the most common inclusion in Mozambique ruby is rutile silk. The rutile forms as high-relief twinned needles with tiny re-entrant angles at the broad end, attached to “daughter” crystals of lower relief. During heat treatment, the daughter crystals may show breakdown in the form of bubbles or mottling.

Natural ruby inclusions may include mineral crystals, rutile silk, healed fissures, fluid inclusions, negative crystals, color zoning and other features formed during or after crystal growth. Such features are important to gemologists because they can provide evidence useful in identifying ruby, understanding its geological history, recognizing treatment and, in some cases, determining geographic origin.

Natural Ruby Inclusion Photomicrographs

The Hyperion natural ruby gallery includes microscopic features found in rubies from major deposits around the world. Each entry is accompanied by descriptive information and, where available, references to the gemological literature.

What Inclusions Can Reveal About Natural Ruby

Inclusions are an important part of ruby identification. Their form, composition, orientation and alteration can help gemologists distinguish natural ruby from synthetic material, recognize evidence of heat treatment, and study the geological environment in which the ruby formed.

Hyperion combines inclusion photomicrography with supporting gemological information so that individual features can be compared with documented examples from known ruby deposits.

About Hyperion

Hyperion is the Lotus Gemology searchable inclusion database. It allows users to browse gemstone inclusions by gem type, geographic origin, treatment and keyword.

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