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.

The high temperature that this blue sapphire from Madagascar was exposed to during beryllium diffusion treatment melted part of the girdle of the stone. Also, in the lower right corner of the photo is the tiny ablation spot that the LIBS created in order to detect the beryllium.
The rose channels in this Madagascar blue sapphire have melted and begun to “neck down” due to the high temperature it was exposed to during beryllium diffusion treatment.
A subtle sign of treatment. Ruby and sapphire surfaces often develop a melted texture when heated, sometimes forming “frozen” droplets that resemble water but cannot be wiped away. To minimize this appearance, stones are frequently repolished. In this case, a few facets were missed, leaving behind telltale signs of heat treatment.
A bubble is present in this cavity in a blue sapphire treated with heat and pressure. With the gentle heat of a hot point, we observed that the bubble is mobile. It is unusual to see a mobile bubble present in a heated sapphire, as they may make cavities explode when heated, but it is possible that the addition of pressure kept this inclusion intact.
These dotted outlines, sometimes called “crop circles,” can occasionally be found in blue sapphires heated at high temperatures. While frequently associated with beryllium diffused stones, they are not conclusive evidence of diffusion treatment. The stone pictured here was heated, but showed no evidence of beryllium diffusion.
A multitude of prismatic apatite crystals are dispersed across this blue sapphire from Mogok, Myanmar. Apatite, a calcium phosphate mineral, is a common guest in corundum and many other gemstones.
This blue sapphire from Myanmar’s Mogok Valley contains several prismatic apatite crystals. Observation between crossed polarized filters reveals not only the bright interference colors of the apatite, but also of its sub-inclusions.
This high temperature heat-treated blue sapphire from a basalt-related source displays zoned internal diffusion. The high temperature (usually above 1600˚C) causes the rutile needles to dissolve and release titanium into the host sapphire, the titanium pairs with the iron in the stone and this creates blue color around the rutile silk remnants.
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.

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.

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