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.

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.
A deep blue color zone is visible in this Madagascar sapphire. Note that the deep blue zone is devoid of turbidity, while the surrounding area is extremely cloudy. This shows a lack of internal diffusion and thus offers evidence that the stone has not been subjected to high-temperature heat treatment.
An unheated fingerprint with many small channels showing no signs of heat-induced damage are a welcome sight in this sapphire from Madagascar.
An unheated fingerprint with many small channels showing no signs of heat-induced damage are a welcome sight in this sapphire from Madagascar.
Texture clouds form sharp, angular zones in this Cambodian sapphire.
Tiny red uranium pyrochlore crystals glow in this sapphire from Pailin, Cambodia. These crystals are a diagnostic inclusion for magmatic sapphires.
This transparent crystal was an obstacle to this sapphire’s growth, creating a “comet trail” stream of fine particles behind it. This example is in a Pailin sapphire.
A tiny red uranium pyrochlore octahedron glows in this sapphire from Pailin, Cambodia. These pyrochlore crystals are a diagnostic inclusion for magmatic sapphires.
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.
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.
Small, blocky black uraninite crystals and rounded, transparent zircon crystals such as these are commonly found in Sri Lankan sapphire. While at first their shiny halos may seem like evidence of heat treatment, they can actually occur naturally, as in this stone. The undissolved rutile silk needles in this stone demonstrate that it has not been heated at a high temperature.
A small black uraninite crystal with shiny fissures around it. While at first this may seem like evidence of heat treatment, these halos can actually occur naturally, as in this stone. The undissolved rutile silk needles in this stone demonstrate that it has not been heated at a high temperature.

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.