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.

When a rutile-silk containing sapphire is heated, titanium from the rutile dissolves into the surrounding sapphire. Once in solid solution, the titanium reacts with iron, creating a blue color. The result is tiny blue halos surrounding the remnants of the rutile silk, a process dubbed “inkspot internal diffusion” by John Koivula. This partially dissolved silk with blue color concentrations is a clear sign that the sapphire was heated.
A melted “snowball” crystal is ensconced in heat-altered fingerprints in this heated sapphire from Sri Lanka. Such “snowballs” and bubbly fingerprints are typical of stones heated at high temperatures.
These droplet-like surface markings may superficially look like water or oil, but they cannot be wiped or scraped off. They are actually spall marks, a result of heat treatment that affects the surface of the stone. Often a heated stone will be repolished to remove such markings.
Iridescent fissures light up the interior of this heat-treated Ceylon sapphire in a spectacular display of colors.
A melted “snowball” crystal is surrounded by a fingerprint showing many small bubbles, a sign of heat alteration. This inclusion is typically found in heated Sri Lankan sapphire.
The shiny, droplet-like marks on the surface may look like water or oil, but they are actually spall marks. They do not rub or scrape off, but are fused onto the surface as a result of heat treatment. This example is on a heated Madagascar pink sapphire.
A melted crystal surrounded by an unusual bronze discoid with a glassy surface. This shiny, glassy appearance provides evidence that the stone was heated.
Melted crystals with a frosted surface, surrounded by heat-altered fingerprints in a heat-treated sapphire from Sri Lanka. Note the hexagonal symmetry of the fingerprint, which shows that it lies in the basal plane.
A heat-altered fingerprint at the culet of a heat-treated sapphire from Sri Lanka. Note the small microfractures and discoids that result from explosion of the individual negative crystal channels that make up the fingerprint.
Four titanium lattice-diffused sapphires surround a natural untreated sapphire. The characteristic dark girdles and highlighted facet junctions of the lattice-diffused sapphires are readily apparent.
This Burmese sapphire was diffused with titanium to induce both a blue color and a star. One can see bleeding of blue color into both surface openings and melted crystals due to the high temperatures used.
This Burmese sapphire was diffused with titanium to induce both a blue color and a star. The rutile silk in such a diffused star occurs in extremely short needles in a shallow layer at and just below the surface.

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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