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.

Wispy, cottony diaspore silk, as depicted here, is a common inclusion in rubies from Myanmar’s Mong Hsu mines.
A small crystal, probably hematite, is surrounded by a metallic fissure with a dendritic pattern. Metallic crystals are commonly seen in rubies from the Baringo area.
The hexagonal zones in this ruby display a characteristic chalky fluorescence in short wave UV. This is typical in heated Mong Hsu rubies. Prior to heat treatment, the hexagonal core of the crystal is typically blue. Heat treatment removes the blue cores, but also alters the exsolved diaspore particles, and changes the infrared spectrum, assisting detection.
A fingerprint, or partially healed fissure, in a heated Thai ruby. Note the rounded, slightly melted edges.
Reminiscent of a butterfly wing, the staining on the fissure in this ruby creates a beautiful pattern.
When observed with reflected light, this cavity in a ruby displays a clear difference in luster when compared to the surrounding corundum. This lower luster and the gas bubble visible in the bottom right corner provide evidence that the stone has been glass filled.
The rounded gas bubble in the corner of this cavity is a clue that the cavity has been filled with glass. Some of the melted fingerprints in the background also suggest that their ruby host was heated.
Agglomeration of apatite (medium luster), phlogopite (low luster) and graphite (high luster) – identified by micro Raman spectroscopy – in a Nepal (Chumar) ruby. Specimen courtesy of Dudley Blauwet.
Agglomeration of apatite (colorless), phlogopite (orange) and graphite (black) – identified by micro Raman spectroscopy – in a Nepal (Chumar) ruby. Specimen courtesy of Dudley Blauwet.
When a gem is heated, it and everything contained in it expands, governed by each material’s coefficient of thermal expansion. Should an included crystal expand more than the host, the result is a tension fissure, such as this around a mica crystal in this heated Mozambique ruby.
Rose channels are often confused with rutile silk in corundum, but they are easily distinguished as they run in entirely different crystallographic directions. Rutile silk unmixes in three intersecting directions (60/120°) parallel to the faces of the hexagonal prism in the plane of the basal pinacoid. In contrast, Rose channels form parallel to the edges of the rhombohedron, in three directions, but only two in the same place. They intersect at 86.1/93.9°. This ruby from Kiteto, Tanzania shows nice examples.
Angular milky texture clouds in a ruby from Rolela, Kiteto, Tanzania.

Search the Complete Hyperion Database

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.