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.

Internal diffusion caused by heat treatment of a titanium-bearing crystal causes the blue color concentration in this Malawi sapphire.
This pale sapphire has been soaked in blue dye to deepen its color. Under the microscope one can clearly see the blue stains in the fissures.
An iridescent fissure surrounds a small crystal in this basaltic sapphire from Bo Ploi, Thailand. When an included crystal such as this is heated, it expands, producing pressure on the host. The easiest release of that pressure is generally in the basal plane, producing a flat “discoid” fissure such as this.
Undissolved rutile silk in fine needles is seen against a backdrop of fine exsolved particles in this padparadscha sapphire from Sri Lanka.
These long growth tubes with glassy areas show clear signs of heat alteration.
In the foreground on the left, a spall mark is visible, providing a piece of evidence that this stone was heated. Although it looks like a small water droplet, it is “frozen” in place and cannot be rubbed or scraped off. In the background, we also see a shiny melted crystal “discoid,” confirming that the stone is heated.
Heat-altered fingerprint in a heat-treated yellow sapphire from Sri Lanka. Note the small burst clouds around the fingerprint channels.
Surface-conformal color rim in a Madagascar pink sapphire that was diffused with beryllium to give it the appearance of a padparadscha sapphire.
A narrow and deeply indented natural on the girdle of a Madagascar sapphire. These features are quite common on Madagascar sapphires of all colors.
This color-change sapphire from Madagascar contained many zircon crystals that showed clear evidence of heat treatment, including cloudiness.
This color-change sapphire from Madagascar contained many zircon crystals that showed clear evidence of heat treatment, including cloudiness and glassy discoid fractures around them.
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.

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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