Heated Sapphire Inclusions

First Published: 7 September 2026

Heated Sapphire Inclusions

Explore inclusions in heat-treated sapphire in Hyperion, the Lotus Gemology inclusion database. Hyperion contains photomicrographs of inclusions and internal features in natural sapphires that have been subjected to heat treatment, documented with information on geographic origin, lighting conditions, field of view, photographer and published references.

Iridescent thin films in this fingerprint create a stunning display of color in their sapphire host.
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.
This sapphire was treated with heat and pressure.
When this heat and pressure treated sapphire was viewed under crossed polars, several small strain patterns became visible.
A chalky, angular appearance is apparent when this sapphire is viewed in shortwave UV illumination.
This heat-treated blue sapphire from Madagascar showed unusual features just below the surface. Note the series of bubbly fingerprints and at the center a cavity featuring two frozen bubbles.
The frosted surface of this large crystal and drippy, melted appearance of the associated fingerprint provide evidence that this sapphire has undergone heat treatment.
The glassy discoids shown here provides strong evidence that their yellow sapphire host was heated.
The melted crystal shown here provides strong evidence that its yellow sapphire host was heated.
This heated pink sapphire displayed a bold chalky angular zoning pattern interspersed with its strong red fluorescence when observed in shortwave illumination.
A small, chalky fluorescent patch can be observed when carefully examining this heated yellow sapphire in short wave UV illumination.
The healing pattern of this healed fissure in a Sri Lankan sapphire suggests it lies along a pyramid face, oblique to the c-axis. Should it lie perpendicular to the c-axis, the healing would reveal triangular or hexagonal healing; if parallel to the c-axis, the healing would be rectangular. Thus the nearly rectangular healing reveals its orientation along a pyramid face close to the c-axis. The use of oblique illumination reveals far more surface detail than ordinary dark or light field.

Heat treatment can alter inclusions and other internal features in sapphire. Changes may include modification or dissolution of rutile silk, alteration of mineral crystals, decrepitation of fluid inclusions, changes to healed fissures and the formation of heat-related features. Such evidence can be important in determining whether a sapphire has been heated.

Heated Sapphire Inclusion Photomicrographs

The Hyperion heated sapphire gallery includes microscopic features documented in heat-treated natural sapphires. Each entry is accompanied by descriptive information and, where available, references to the gemological literature.

What Inclusions Can Reveal About Heat Treatment

Microscopic examination is an important part of detecting heat treatment in sapphire. The condition of mineral inclusions, rutile silk, fissures and other internal features can provide evidence of exposure to elevated temperatures. These features are evaluated together with other gemological observations when determining treatment status.

Hyperion combines inclusion photomicrography with supporting gemological information so that heat-related features can be compared with documented examples in treated sapphires.

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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