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 crystal containing birefringent diaspore needles needles and a small graphite plate; unheated Sri Lanka sapphire
Unusual birefringent crystals in a low-relief partially healed fissure in a sapphire treated with high-temperature heat plus modest pressure (HT+P). When tested with Lotus Gemology’s microraman, they proved to be corundum. It is thought that they crystallized during the treatment process.
Unusual birefringent crystals in a low-relief partially healed fissure in a sapphire treated with high-temperature heat plus modest pressure (HT+P). When tested with Lotus Gemology’s microRaman, they proved to be corundum. It is thought that they crystallized during the treatment process.
A metallic black plate was found in this untreated Sri Lankan sapphire. Microraman analysis in Lotus Gemology’s Bangkok lab showed it to be graphite.
A cluster of small metallic black plates was found in this untreated Sri Lankan sapphire. Microraman analysis in Lotus Gemology’s Bangkok lab showed them to be graphite.
Angular cloud of particles in sapphire. Such dense “texture clouds” are often a sign of high-temperature heat treatment; FOV~ 7 mm
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.
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.
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.
Abraded facet junctions on an untreated Sri Lanka sapphire. According to Robert Webster’s “Gems” (1st edition, 1962, p. 66): “Corundum is a hard stone, indeed the impure material is used as an abrasive, and is rated 9 on the scale of hardness devised by F. Mohs. Despite the hardness of the mineral, however, ruby and sapphire need to be handled with some care, for they are to a slight extent brittle and if dropped on a hard surface or given a sharp blow tend to develop internal flaws and cracks.”

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.

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