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.

Rose channels (formerly thought to be boehmite needles) forming Star of David pattern in a flux healed Greenland pink sapphire. FOV ~2.5 mm
Rose channels (formerly thought to be boehmite needles) forming Star of David pattern in a flux healed Greenland pink sapphire.
Melted crystal with frozen bubble in sapphire. When a gem is heated, included crystals may melt and cool into a glass. Because the glass takes up less volume than the previous solid crystal, a contraction bubble forms in the glass; FOV ~2.5 mm
Melted crystals with circular heat-induced “bubbly” fingerprints and partially dissolved silk in a heated sapphire from Sri Lanka; FOV 2 mm
Small crystals with decolorized areas around growth tubes cut through on the surface. The growth tubes have apparently drawn titanium out of solid solution in the sapphire, thus cannibalizing the color.
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.
This cluster of melted crystals with a frosty “snowball” appearance and glassy discoid around them is a clear sign that their sapphire host has been heat treated.
Angular zoned chalky shortwave fluorescent reaction, indicative of heat treatment.
The melted, shiny fissure around this small crystal represents clear evidence that the sapphire host has been heat treated.

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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.