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.

A deep orange plate of phlogopite mica drifts on a background of silk in this sapphire from Serendib. The undamaged nature of the mica and silk demonstrate that this stone has not been subjected to high-temperature heat treatment.
A graphite crystal is encapsulated within a negative crystal in this unheated Ceylon sapphire. On the left we can see iridescent flecks of undissolved “silk,” providing further evidence that the stone is untreated.
A graphite crystal is encapsulated within a negative crystal in this unheated Ceylon sapphire.
In the foreground on the left, a spall mark is visible, providing a piece of evidence that this stone was heated. Although it looks like a small water droplet, it is “frozen” in place and cannot be rubbed or scraped off. In the background, we also see a shiny melted crystal “discoid,” confirming that the stone is heated.
Elongated negative crystals filled with a birefringent substance glow in this Sri Lankan sapphire in crossed polars.
An elongated negative crystal filled with a birefringent substance glows in this Sri Lankan sapphire in crossed polars.
Extremely sharp angular growth zoning as is typically seen in Madagascar sapphire.
Transparent, doubly refractive crystals in sapphire from Nigeria’s Mambilla region.
One of the more unusual inclusions we have encountered in sapphires from Nigeria’s Mambilla area are these deep red crystals. They are unlike anything we’ve seen in sapphires from other localities and are currently under investigation to determine their identity.
This image clearly illustrates what master photomicrographer John Koivula has termed “chromophore cannibalization.” As titanium is drawn out of solid solution to form exsolved rutile silk, the area in the vicinity is decolorized, losing its blue color. This is a natural process and is the reverse of “internal diffusion,” where heat treatment sends the titanium back into solution, creating blue clouds or “inkspots” around the rutile remnants.
Extremely sharp and angular growth zoning in a sapphire from Nigeria. This is a common feature in blue sapphires from this West African country.
Ilmenite silk in a sapphire from Myanmar’s Mogok Stone Tract.

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