Treated Sapphire Inclusions

First Published: 7 September 2026

Treated Sapphire Inclusions

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

Shiny, glassy discoids and frosted crystals display clear evidence that this sapphire was heated.
A zoned, chalky appearance in shortwave UV illumination is a sign of heat treatment in sapphire.
Small glassy discoids embedded in a partially healed fissure provide evidence that this sapphire was heated.
This sapphire was treated with heat at high temperatures, which melted its surfaces, creating the unusual appearance of recrystallized corundum on the surface.
A glassy discoid around a tiny melted crystal provides evidence that this inclusion’s sapphire host has been heated. Specimen courtesy Tristan Knowles.
A “ghost” fissure in a Sri Lankan sapphire treated with high-temperature heating plus pressure (HT+P). In crossed polars, the fissure shows transparent doubly refractive crystals. These have previously been identified as corundum by Lotus gemologists using microRaman. These tiny synthetic corundum crystals form during the treatment. Nathan Renfro of the GIA was the first to notice these ghost crystals. E. Billie Hughes of Lotus Gemology was the first to identify them. FoV=4 mm.
A “ghost” fissure in a Sri Lankan sapphire treated with high-temperature heating plus pressure (HT+P). In parallel polars, the fissure shows transparent doubly refractive crystals. These have previously been identified as corundum by Lotus gemologists using microRaman. These tiny synthetic corundum crystals form during the treatment. FoV=4 mm.
A “ghost” fissure in a Sri Lankan sapphire treated with high-temperature heating plus pressure (HT+P). In light field illumination, the fissure shows low-relief crystals. FoV=4 mm.
Red pyrochlore crystals like this one, which was identified with microraman spectroscopy, are a common inclusion in basalt-related sapphire.
Heat treatment of this pink sapphire has caused small negative crystal inclusions to burst, creating shiny discoid fractures around the crystals.
Angular zoned chalky fluorescence like this is a tell-tale sign of heat treatment.
Angular zoned chalky fluorescence like this is a tell-tale sign of heat treatment.

Treatment can alter existing inclusions and produce new microscopic features in sapphire. These may include changes to mineral inclusions, altered rutile silk, tension fractures, healed fissures, residues and other features associated with heating, diffusion, fissure filling and other treatment processes.

Treated Sapphire Inclusion Photomicrographs

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

What Inclusions Can Reveal About Sapphire Treatment

Microscopic examination is an important part of detecting treatment in sapphire. The appearance and alteration of inclusions, fractures and growth features can provide evidence of treatment and, in some cases, information about the processes to which a sapphire has been subjected.

Hyperion combines inclusion photomicrography with supporting gemological information so that treatment-related features can be compared with documented examples in natural sapphire.

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