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.

High-temperature heat treatment has the potential to alter certain types of solid inclusions. Here we see an included crystal that melted during heat treatment, turning into glass. Because a glass takes up less volume than a crystal, the result is a void, in the form of a bubble within the glass.
Irregular crystals are seen against a backdrop of sharp angular growth zoning in this untreated sapphire from Madagascar.
Pink sapphires from Sri Lanka are routinely heated at relatively low temperatures (>1200°C) to drive off the blue tint. While this rarely changes the inclusions, it can be unmasked by reference to the shortwave ultraviolet fluorescence, which often develops chalky zones, as shown in this stone.
An iridescent secondary fingerprint inclusion in a pink sapphire from Sri Lanka. The healing pattern reveals the underlying atomic symmetry. In this case, the hexagonal healing structure show that the fingerprint lies in the plane of the basal pinacoid.
An unusual green crystal was found trapped in this unheated blue sapphire from Serendib, with a cloud of rutile silk trailing in its wake.
An unusual green crystal was found trapped in this unheated blue sapphire from Serendib.
When a rutile-silk containing sapphire (such as this stone from Kanchanaburi, Thailand) is heated, the titanium from the rutile moves into solid solution in the sapphire, coloring the area around the rutile blue, creating a distinctive “ink spot” internal diffusion pattern.
Fingerprints are similar to scars, representing the healing of earlier wounds. This example shows how a formerly open fissure has healed shut, with tiny flattened negative crystals being all that is left of the open space of the previous fissure.
A triangular growth twin peeks out near the culet of this unheated violet sapphire from Sri Lanka.
One of the classic inclusions found in Sri Lankan sapphires are negative crystals. These are generally filled with liquid carbon dioxide and sometimes contain a gas phase, too. In addition, hexagonal black graphite plates and slender diaspore needles are frequent guests in these tiny primary cavities.
One of the classic inclusions found in Sri Lankan sapphires are negative crystals. These are generally filled with liquid carbon dioxide and sometimes contain a gas phase, too. In addition, hexagonal black graphite plates and slender diaspore needles are frequent guests in these tiny primary cavities.
One of the classic inclusions found in Sri Lankan sapphires are negative crystals. These are generally filled with liquid carbon dioxide and sometimes contain a gas phase, too. In addition, hexagonal black graphite plates and slender diaspore needles are frequent guests in these tiny primary cavities.

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.