Sapphire Inclusions

First Published: 7 September 2026

Sapphire Inclusions

Explore sapphire inclusions in Hyperion, the Lotus Gemology inclusion database. Hyperion contains photomicrographs of inclusions and internal features in natural sapphire, documented with information on geographic origin, treatment, lighting conditions, field of view, photographer and published references.

Iron rich sapphire often contain “silk” in the form of these irregularly shaped platelets. Notice that reflected light can produce a variety of interference colors (left side of image) while transmitted light shows that the platelets have a brown body color (right side of image).
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.
Negative crystals can contain a variety of substances. In this example, on the left we see what are likely diaspore needles, then a graphite flake in the center, and a gas bubble on the right. All show no signs of heat treatment. The gas bubble is the gaseous phase of the liquid carbon dioxide that fills the cavity.
Looking at this image, it’s easy to see why gemologists use the term “fingerprint” to describe partially healed fissures.
These brown crystals (probably phlogopite mica) show no signs of heat damage in their Sri Lankan sapphire host.
These brown crystals (probably phlogopite mica) show no signs of heat damage in their Sri Lankan sapphire host.
Often chalky shortwave fluorescence is a sign of heat treatment in sapphire, but some stones from Madagascar, like this one, show a superficially chalky patch that is not associated with heat treatment.
Overhead lighting was used to photograph this scene in a violet sapphire from Sri Lanka, which shows two large mica plates. The undamaged state of the mica reveals that this sapphire has not been subjected to heat treatment.
A combination of dark field and overhead lighting was used to photograph this scene in a violet sapphire from Sri Lanka, which shows two large mica plates and smaller rounded zircon crystals. The undamaged state of the mica reveals that this sapphire has not been subjected to heat treatment.
A crystal filled with an unknown yellow substance stands out against its sapphire-blue background.
This image clearly illustrates what master photomicrographer John Koivula has termed “chromophore cannibalization.” As titanium is drawn out of solid solution to form exsolved rutile silk, the area in the immediate vicinity is decolorized, losing its blue color.

Search the Complete Hyperion Database

Sapphire inclusions may include mineral crystals, rutile silk, healed fissures, fluid inclusions, negative crystals, color zoning and other features formed during or after crystal growth. Such features are important to gemologists because they can provide evidence useful in identifying sapphire, understanding its geological history, recognizing treatment and, in some cases, determining geographic origin.

Sapphire Inclusion Photomicrographs

The Hyperion sapphire gallery includes microscopic features found in sapphires from major deposits around the world. Each entry is accompanied by descriptive information and, where available, references to the gemological literature.

What Inclusions Can Reveal About Sapphire

Inclusions are an important part of sapphire identification. Their form, composition, orientation and alteration can help gemologists distinguish natural sapphire from synthetic material, recognize evidence of heat treatment, and study the geological environment in which the sapphire formed.

Hyperion combines inclusion photomicrography with supporting gemological information so that individual features can be compared with documented examples from known sapphire deposits.

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.