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.

These dotted outlines, sometimes called “crop circles,” can occasionally be found in blue sapphires heated at high temperatures. While frequently associated with beryllium diffused stones, they are not conclusive evidence of diffusion treatment. The stone pictured here was heated, but showed no evidence of beryllium diffusion.
Rainbow connection. Microscopic thin films create an iridescent burst of color in this untreated sapphire.
A small platelet is surrounded by rutile silk in this unheated sapphire.
Suspended in time, a negative crystal encapsulates part of the Earth’s history in this pink sapphire.
A partially healed fissure, or fingerprint, can be observed in this sapphire. The angular healing patterns form naturally due to the crystalline structure of the gem.
God’s thumbprint. When magnified, a partially healed fissure can be seen in this sapphire. It’s easy to see why gemologists have nicknamed these inclusions “fingerprints.”
These two elongated zircon crystals appear to float above the deep blue color zones of this sapphire from Madagascar. The microfissures surrounding the crystals are a result of radiation from the thorium and uranium traces in the zircon.
A multitude of prismatic apatite crystals are dispersed across this blue sapphire from Mogok, Myanmar. Apatite, a calcium phosphate mineral, is a common guest in corundum and many other gemstones.
This blue sapphire from Myanmar’s Mogok Valley contains several prismatic apatite crystals. Observation between crossed polarized filters reveals not only the bright interference colors of the apatite, but also of its sub-inclusions.
This sapphire contains fine, milky texture clouds that create a “velvety” glow.
This high temperature heat-treated blue sapphire from a basalt-related source displays zoned internal diffusion. The high temperature (usually above 1600˚C) causes the rutile needles to dissolve and release titanium into the host sapphire, the titanium pairs with the iron in the stone and this creates blue color around the rutile silk remnants.
Rutile silk needles are well-known inclusions in Burmese corundum, but rutile can appear in other forms as well. Here, a red rutile crystal (identified with micro Raman) is a prominent feature in this sapphire. Specimen courtesy Vincent Pardieu.

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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