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.

Small “frozen” gas bubbles trapped in place inside negative crystals provide evidence that a stone has been heated, as seen in this example in a basalt-related sapphire.
Laser-Induced-Breakdown-Spectroscopy (LIBS) is used by some gem labs to test for beryllium. Unlike Laser Ablation Inductively Coupled Plasma Mass Spectroscopy (LA-ICPMS), the surface is actually melted (rather than ablated), producing the circular rippled mark we see in the center of the girdle on this stone.
Resembling a large insect, this crystal with a discoid fissure was found in a heat-treated padparadscha sapphire from Madagascar.
A small crystal with an iridescent thin-film decrepitation halo surrounding it. When a crystal is heated (either by a magma or artificially by human intervention), it expands. Tension is often relieved by a fissure in the weakest direction, the basal plane.
A small crystal with an iridescent thin-film decrepitation halo surrounding it. When a crystal is heated (either by a magma or artificially by human intervention), it expands. Tension is often relieved by a fissure in the weakest direction, the basal plane.
Dense texture clouds made of tiny exsolved particles form angular zones in this heated Madagascar sapphire.
Frosty melted “snowball” crystals provide evidence that this Madagascar sapphire was heat treated.
Frosty melted “snowball” crystals provide evidence that this Madagascar sapphire was heat treated.
Orange crystals seem to float against a midnight blue sky, with angular growth zoning visible in the background, in this sapphire from New South Wales, Australia. Specimen courtesy of Terrence Coldham.
Small spotted platelets spread across the blue skies of this Madagascar sapphire.
This heated sapphire shows signs of treatment with these shallow, heat-altered fingerprints.
This elongated cavity is starting to show the signs of melting as a result of heat treatment as the edge become rounded.

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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.