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.

Tiny black dendrites inhabit the sticky blue world of this sapphire from Madagascar, growing amidst the small pockets of undigested fluid in a fingerprint.
A complex structure of tiny exsolved particles and milky texture clouds outline the shape of this crystal at an earlier stage in its growth. This stone is from Queensland’s Lava Plains mines.
Exsolved rutile silk lights up the interior of this natural blue sapphire from Sri Lanka. It is these inclusions that give rise to the stars in cabochon-cut stones.
When a rutile-silk containing sapphire is heated, titanium from the rutile dissolves into the surrounding sapphire. Once in solid solution, the titanium reacts with iron, creating a blue color. The result is tiny blue halos surrounding the remnants of the rutile silk, a process dubbed “inkspot internal diffusion” by John Koivula. This partially dissolved silk with blue color concentrations is a clear sign that the sapphire was heated.
The clear, undamaged, euhedral form of this crystal, suspended in its sapphire host, provides evidence that the stone is unheated.
Polysynthetic twinning is secondary twinning, forming after the host crystal grew. When the stone is placed between crossed polars, the dazzling colors of these polysynthetic twin planes can be easily seen.
Like Mother Nature’s snow globe, Sri Lankan sapphire often has negative crystals containing other inclusions. In this example we can see small diaspore needles and black graphite flakes inside the cavities.
A deep blue color zone is visible in this Madagascar sapphire. Note that the deep blue zone is devoid of turbidity, while the surrounding area is extremely cloudy. This shows a lack of internal diffusion and thus offers evidence that the stone has not been subjected to high-temperature heat treatment.
A melted “snowball” crystal is ensconced in heat-altered fingerprints in this heated sapphire from Sri Lanka. Such “snowballs” and bubbly fingerprints are typical of stones heated at high temperatures.
An unheated fingerprint with many small channels showing no signs of heat-induced damage are a welcome sight in this sapphire from Madagascar.
An unheated fingerprint with many small channels showing no signs of heat-induced damage are a welcome sight in this sapphire from Madagascar.
Texture clouds form sharp, angular zones in this Cambodian sapphire.

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.

Search the Complete Hyperion Database