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.

This untreated Ceylon sapphire showed an unusual inclusion in the form of a small transparent crystal with two black grains embedded in it. Surrounding this was a flat fissure with a reddish color in transmitted light. It is possible that this is a zircon crystal with embedded uraninite and the reddish stain in the fissure is due to radiation from the zircon/uraninite.
Feldspar crystals are a frequent guest of sapphires derived from basalt deposits. Thus it was no surprise when the three larger crystals show here turned out to be feldspar. The identification was made with Lotus Gemology’s micro Raman unit. Examination with crossed polars reveals the doubly refractive nature of the feldspar guest inclusions.
Spall marks from heating on the pavilion of a heat-treated Kashmir (India) sapphire.
Iron-rich silk with a “hairy” appearance lights up the interior of this sapphire.
Rows of negative crystals in a Madagascar sapphire. The fact that these show no damage are strong evidence that the gem has not been heat treated.
A secondary liquid inclusion in an untreated Ceylon sapphire. The healing pattern suggests that this fingerprint formed oblique to the c-axis.
A secondary liquid inclusion explodes with color when lit from above. The healing pattern suggests that this fingerprint formed oblique to the c-axis.
Written in stone. A large negative crystal appears to have inscribed a delicate pattern in this untreated sapphire from Sri Lanka.
We noticed a transparent birefringent crystal in this blue sapphire from Madagascar. Its luster was lower than the sapphire, indicating a lower RI than the host. Testing with Lotus Gemology’s micro Raman revealed it to be grandidierite. This is the first discovery of grandidierite in corundum.
We noticed a transparent birefringent crystal in this blue sapphire from Madagascar. Its luster was lower than the sapphire, indicating a lower RI than the host. Testing with Lotus Gemology’s micro Raman revealed it to be grandidierite. This is the first discovery of grandidierite in corundum.
We noticed a transparent birefringent crystal in this blue sapphire from Madagascar. Its luster was lower than the sapphire, indicating a lower RI than the host. Testing with Lotus Gemology’s micro Raman revealed it to be grandidierite. This is the first discovery of grandidierite in corundum.
Dark blue color zones such as this surrounded by milky areas are a common feature of Madagascar sapphire from the Ilakaka region; sometimes these stones are confused with those from Kashmir; FOV 5.5 mm

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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