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 sapphire contained several platey metallic crystals. While we were not able to get a conclusive match on this particular crystal, one of the other crystals in the stone that was cut through on the surface was a good match for graphite, suggesting that this crystal might be graphite as well.
When examining this pink sapphire from Madagascar we spotted this interesting white crystal cut through on the surface. Micro Raman spectroscopy identified the crystal as andalusite.
A rounded zircon crystal is cut through in this untreated sapphire from Myanmar (Burma). Its identity was confirmed with micro Raman.
These small irregular crystal grains were identified via micro Raman as anorthite feldspar.
These small irregular crystal grains were identified via micro Raman as anorthite feldspar.
This sapphire from Myanmar’s Mogok Stone Tract displays a classic fingerprint inclusion in a spider’s web shape. The plane of the inclusion is close to the basal plane. As a result, the healed areas have a hexagonal shape.
Another common guest mineral in sapphire is phlogopite mica, which is typically brown or orange in color. This example was identified as fluorapatite by micro Raman.
A common guest mineral in sapphire is apatite. These can take on a variety of forms, from rounded balls, such as that shown here, to hexagonal prisms and dog’s tooth shapes. This example was identified as fluorapatite by micro Raman.
This untreated pink sapphire from the Ilakaka area of Madagascar was part of a large parcel purchased from a miner by the author in 2005. It contains rounded zircon crystals, and blocky crystals, some with fringes. The crystal in the center was identified as muscovite mica by micro Raman.
This untreated pink sapphire from the Ilakaka area of Madagascar was part of a large parcel purchased from a miner by the author in 2005. It contains zoned clouds of fine rutile dust, rounded zircon crystals, and in the center, an irregular rounded crystal that was identified by micro Raman as anorthite, one of the end members of the plagioclase feldspar series.
This yellow sapphire displays a striking angular, superficial chalky patch when viewed in shortwave UV illumination. This is the first time we have seen this reaction in a yellow sapphire that shows no signs of heat treatment, with all inclusions (intact negative crystals) and spectral information (strong 3160 in the infrared) pointing to an untreated gem. We have seen this reaction occasionally in untreated blue sapphires from Madagascar.
A superficial chalky patch is visible when this sapphire is viewed under shortwave UV illumination. While a chalky shortwave UV fluorescence is generally a strong indicator of heat treatment, on occasion we have seen these superficial patches in stones we believe to be untreated.

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.