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.

Small black uraninite crystals with shiny fissures around them in a Sri Lankan sapphire. While at first these 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.
Many crystals contain shallow fissures on their surfaces. In sapphires from Sri Lanka, Myanmar and Madagascar, these fissures often contain yellow stains. High-temperature heating not only destroys the yellow stains, but begins a process of healing, where the fissures turn white and start forming fingerprints.
Dense clouds of exsolved titanium-bearing minerals have created the fanciful scenery within this untreated sapphire from Madagascar. As the crystal cooled these growing clouds sucked titanium from the surrounding sapphire, thus robbing it of an essential chromophore. The result is decolorized zones surrounding the clouds, a process dubbed “chromophore cannibalization” by microphotographic maestro John Koivula.
Sharp angular growth zoning, which is typical in Madagascar sapphire. This can help separate natural stones from Verneuil flame fusion synthetics, which have curved color banding.
These fine parallel lines show the sharp angular growth zoning typical in Madagascar sapphire. These lines can be distinguished from polishing lines because they cross several facets.
A long, orange-stained growth tube pierces this Madagascar sapphire. These fine growth tubes are a common feature in sapphire from Madagascar.
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.
Undissolved rutile silk in a Mogok sapphire. Such silk creates the stars in star sapphire and ruby.
Undissolved rutile silk in a Mogok sapphire. The intact nature of the silk demonstrates that this stone has not been subjected to high-temperature heat treatment.
Winged zircon crystal hovering within a sapphire from Myanmar’s Mogok Stone Tract.
Orange primary rutile crystals stand out against a backdrop of exsolved particles in a hexagonal pattern in this Montana sapphire.

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.