Ceylon Sapphire Inclusions

First Published: 7 September 2026

Ceylon Sapphire Inclusions

Explore Ceylon sapphire inclusions in Hyperion, the Lotus Gemology inclusion database. Hyperion contains photomicrographs of inclusions and internal features in natural sapphires from Sri Lanka (Ceylon), documented with information on treatment, lighting conditions, field of view, photographer and published references.

Negative crystals like these can trap other materials inside, forming a natural time capsule. In this case, we can see small black flakes of graphite suspended within the negative crystals in this unheated sapphire from Sri Lanka. Pristine negative crystals such as this offer evidence that the gem has not been subjected to heat treatment.
Clustered negative crystals like these grew syngenetically, meaning at the same time as their sapphire host. Note their angular “euhedral” shapes. Many contain black flakes of graphite.
The fingerprint in this sapphire shows clear signs of heat alteration. Note the frosty, hazy appearance between the negative crystals, which results from micro-fractures to release the pressure caused by heating; also note that each negative crystal tube has begun to neck down and become more rounded.
This cluster of melted crystals with a frosty “snowball” appearance and glassy discoid around them is a clear sign that their sapphire host has been heat treated.
A rectilinear fingerprint shines brightly inside this untreated sapphire from Sri Lanka.
Iron rich sapphire often contain “silk” in the form of these irregularly shaped platelets. Notice that reflected light can produce a variety of interference colors (left side of image) while transmitted light shows that the platelets have a brown body color (right side of image).
The melted, shiny fissure around this small crystal represents clear evidence that the sapphire host has been heat treated.
Negative crystals can contain a variety of substances. In this example, on the left we see what are likely diaspore needles, then a graphite flake in the center, and a gas bubble on the right. All show no signs of heat treatment. The gas bubble is the gaseous phase of the liquid carbon dioxide that fills the cavity.
Looking at this image, it’s easy to see why gemologists use the term “fingerprint” to describe partially healed fissures.
These brown crystals (probably phlogopite mica) show no signs of heat damage in their Sri Lankan sapphire host.
These brown crystals (probably phlogopite mica) show no signs of heat damage in their Sri Lankan sapphire host.
Overhead lighting was used to photograph this scene in a violet sapphire from Sri Lanka, which shows two large mica plates. The undamaged state of the mica reveals that this sapphire has not been subjected to heat treatment.

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Ceylon sapphire inclusions may include mineral crystals, rutile silk, healed fissures, fluid inclusions, negative crystals, growth features and other internal features formed during or after crystal growth. Such features are important to gemologists because they can provide evidence useful in identifying sapphire and evaluating a possible Sri Lankan origin.

Ceylon Sapphire Inclusion Photomicrographs

The Hyperion Ceylon sapphire gallery includes microscopic features documented in sapphires from Sri Lanka (Ceylon). Each entry is accompanied by descriptive information and, where available, references to the gemological literature.

What Inclusions Can Reveal About Ceylon Sapphire

Inclusions are an important part of geographic origin determination in sapphire. Their form, composition, orientation and associations can provide evidence that, when considered together with other gemological properties, may support or contradict a Sri Lankan origin.

Hyperion combines inclusion photomicrography with supporting gemological information so that individual features can be compared with documented examples from Ceylon sapphires.

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.