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.

Examining the same stone with a powerful shortwave light source shows the chalky fluorescence in a similar pattern, confirming the heat treatment.
In this heated sapphire, one can clearly see “ink spot” internal diffusion, caused when the heat treatment partially dissolves the rutile silk, sending titanium into solid solution. This is a sure sign of high-temperature heat treatment. Check the next photo for the appearance in shortwave ultraviolet light.
Angular cloud of particles in sapphire. Such dense “texture clouds” are often a sign of high-temperature heat treatment; FOV~ 7 mm
Sapphires treated with high temperatures and modest pressure (HT+P) sometimes contain ghost-like fingerprints with low relief crystals, when viewed in transmitted light. In crossed polars, these crystals stand out clearly and are birefringent. Using Lotus Gemology’s micro Raman unit, we have identified these crystals as recrystallized corundum.
Sapphires treated with high temperatures and modest pressure (HT+P) sometimes contain ghost-like fingerprints with low relief crystals, when viewed in transmitted light. In crossed polars, these crystals stand out clearly and are birefringent. Using Lotus Gemology’s micro Raman unit, we have identified these crystals as recrystallized corundum.
The fingerprint in this sapphire shows clear signs of heat alteration. Note the frosty, hazy appearance between the negative crystals, which results from micro-fractures to release the pressure caused by heating; also note that each negative crystal tube has begun to neck down and become more rounded.
The melted, shiny fissure around this small crystal represents clear evidence that the sapphire host has been heat treated.
Chalky shortwave fluorescence follows the pattern of partially dissolved silk in this heated pink sapphire.
Iridescent fissures around small crystals create a floral motif in this heated sapphire.
Streams of fine particles zig-zag across this heated sapphire.
The high temperatures reached during beryllium diffusion have produced melted surfaces on a natural.
Magnification of this beryllium-diffused orange sapphire reveals small areas on the surface where corundum has melted and recrystallized. This is sometimes seen in beryllium-diffused corundums, due to the high temperatures reached during the 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