Sapphire Inclusions

First Published: 7 September 2026

Sapphire Inclusions

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

Bright red mica crystals are scattered across the interior of this Burmese sapphire. The crystals were identified with micro Raman. Specimen courtesy Vincent Pardieu.
Thin films and flat negative crystals light up when illuminated with fiber optic light in this Burmese sapphire. Specimen courtesy Vincent Pardieu.
High temperature heat treatment melted the surface of this sapphire, resulting in recrystallized corundum at and just below the surface.
Some of the small particles in this sapphire are surrounded blue color concentrations. Often termed “internal diffusion,” this occurs when titanium from rutile dissolves (enters into solid solution) into the surrounding sapphire as a result of heat treatment. Once in solid solution, the Ti atoms combine with Fe atoms, producing an intervalence charge transfer that absorbs light.
A pair of tiny crystals surrounded by bubbly fingerprints provide evidence that this sapphire has been heated.
Iridescent thin films in this fingerprint create a stunning display of color in their sapphire host.
Fine channels form a beautiful partially healed fissure in this sapphire, creating a unique “fingerprint” for the stone.
Two euhedral apatite crystals (identified with micro Raman) are suspended inside this unheated sapphire.
This nicely shaped hexagonal crystal caught our eye as we were testing its sapphire host. Analysis with micro Raman identified the metallic crystal as graphite.
Negative crystals filled with an unknown substance (microRaman suggests they could be diaspore) in a sapphire from India’s famous Kashmir mines near Sumjam. Each is surrounded by small decrepitation halos that are parallel to the basal plane.
In this beryllium-diffused green sapphire, the high-temperature heating has healed a former fissure and the pockets of residue show clear rounding and necking down. Some also show shrinkage bubbles as the glassy material cooled and thus occupied less space, creating the bubble in the cavity. Angular growth zoning can be seen in the background.
In this sapphire originating from a basalt-related source, color concentrated in the cloudy zones suggests that it has been subjected to heat treatment. Also visible are zoned clouds of fine exsolved particles.

Sapphire 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 sapphire, understanding its geological history, recognizing treatment and, in some cases, determining geographic origin.

Sapphire Inclusion Photomicrographs

The Hyperion sapphire gallery includes microscopic features found in sapphires 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 Sapphire

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

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

Search the Complete Hyperion Database