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.

Coarse exsolved plates against a backdrop of rutile silk in a sapphire from Mogok, Myanmar.
Crossing twin planes in a sapphire from a basaltic source. These are secondary glide twins, created by pressure after the stone grew, and form parallel to the rhombohedron faces, intersecting at 86.1 and 93.9°.
Birefringent crystals light up between crossed polars in this Ceylon sapphire.
Birefringent crystals light up between crossed polars in this Ceylon sapphire.
An explosion of rutile silk and attached daughter crystals enliven the interior of this sapphire from Serendib.
A brilliantly iridescent fingerprint in a sapphire from Sri Lanka. Such healing patterns reveal the underlying atomic symmetry. In this case, the rectangular healing pattern shows that this fingerprint lies parallel to a prism face.
When a rutile-silk containing sapphire (such as this stone from Nigeria) 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.
An iridescent secondary fingerprint inclusion in a pink sapphire from Sri Lanka. The healing pattern reveals the underlying atomic symmetry. In this case, the rectangular healing structure show that the fingerprint lies in the plane of the hexagonal prism (parallel to the c axis).
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.
When low-iron sapphires are heat treated, a chalky shortwave fluorescence often develops. This generally is related to colorless or lightly colored regions of the gem, and so follows the crystallographic structure, as is seen here. This is strong evidence of heat treatment.
When a rutile-silk containing sapphire (such as this stone from Sri Lanka) 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.
When a rutile-silk containing sapphire (such as this stone from Sri Lanka) 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.

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.

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