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.

Looking like a pistol, a group of three primary rutile crystals sits against a background of secondary rutile silk in this sapphire from Sri Lanka.
Certain type of solid inclusions are heat sensitive and may alter when the gem is heat treated. Here we see crystals that have altered into “snowball” like forms. In addition, the coefficient of thermal expansion of the included crystals was greater than corundum. Thus when heated, they expanded more than the surrounding sapphire, producing glassy discoid fissures.
High-temperature heat treatment has the potential to alter certain types of solid inclusions. Here we see an included crystal that melted during heat treatment, turning into glass. Because a glass takes up less volume than a crystal, the result is a void, in the form of a bubble within the glass.
An unusual green crystal was found trapped in this unheated blue sapphire from Serendib, with a cloud of rutile silk trailing in its wake.
A triangular growth twin peeks out near the culet of this unheated violet sapphire from Sri Lanka.
Heat-altered “snowball” like crystals in a heat-treated sapphire from Sri Lanka.
Heat-altered fingerprints in a heat-treated Ceylon sapphire. Close examination reveals microscopic fractures around each negative crystal, due to the heat treatment.
Rutile consists of titanium dioxide. When a sapphire containing exsolved rutile silk is heated, the rutile melts, sending the titanium back into solution, coloring the stone blue around the now partially dissolved silk. This creates a classic “inkspot” internal diffusion pattern, and is proof of high-temperature heat treatment.
Internal diffusion in heat-treated Ceylon sapphire. This is caused by the bleeding of titanium into the surrounding sapphire from titanium-bearing inclusions such as rutile during high-temperature heat treatment.
An unusual green crystal was found trapped in this unheated blue sapphire from Serendib.
One of the classic inclusions found in Sri Lankan sapphires are negative crystals. These are generally filled with liquid carbon dioxide and sometimes contain a gas phase, too. In addition, hexagonal black graphite plates and slender diaspore needles are frequent guests in these tiny primary cavities.
One of the classic inclusions found in Sri Lankan sapphires are negative crystals. These are generally filled with liquid carbon dioxide and sometimes contain a gas phase, too. In addition, hexagonal black graphite plates and slender diaspore needles are frequent guests in these tiny primary cavities.

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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