Ceylon Star Sapphire Inclusions

First Published: 7 September 2026

Ceylon Star Sapphire Inclusions

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

Fine needles of rutile "silk" create a dazzling display in this untreated sapphire. In this case, the silk is responsible for the asterism (star) effect in the stone.
A euhedral apatite crystal, which was identified with micro Raman, appears to float over a cloud of rutile silk in this Ceylon sapphire.
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.
Small, blocky black uraninite crystals and rounded, transparent zircon crystals such as these are commonly found in Sri Lankan sapphire. While at first their shiny halos may seem like evidence of heat treatment, they can actually occur naturally, as in this stone. The undissolved rutile silk needles in this stone demonstrate that it has not been heated at a high temperature.
A small black uraninite crystal with shiny fissures around it. While at first this may seem like evidence of heat treatment, these halos can actually occur naturally, as in this stone. The undissolved rutile silk needles in this stone demonstrate that it has not been heated at a high temperature.
Small black uraninite crystals with shiny fissures around them in a Sri Lankan sapphire. While at first these may seem like evidence of heat treatment, these halos can actually occur naturally, as in this stone. The undissolved rutile silk needles in this stone demonstrate that it has not been heated at a high temperature.
Like balloons on a string, these unusual crystals of what may be apatite with attached growth tubes, along with a negative crystal, enrich the interior of this purple star sapphire from Sri Lanka.
A single twin plane stands out in brilliant contrast when examined between crossed polars in this star sapphire from Sri Lanka.
Otherworldly birefringent crystals float above a twin plane in a sapphire from Sri Lanka.
Otherworldly birefringent crystals float above a twin plane in a sapphire from Sri Lanka.
Balloons on a string. Unusual crystals of what may be apatite with attached growth tube strings in a purple star sapphire from Sri Lanka.
Unusual crystals of what may be apatite with attached growth tubes in a purple star sapphire from Sri Lanka.

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Ceylon star sapphire inclusions may include oriented rutile silk, mineral crystals, healed fissures, fluid inclusions, growth zoning and other features formed during or after crystal growth. Of particular importance are oriented inclusions capable of producing asterism when the stone is cut with the appropriate orientation.

Ceylon Star Sapphire Inclusion Photomicrographs

The Hyperion Ceylon star sapphire gallery includes microscopic features documented in natural star 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 Star Sapphire

Inclusions are fundamental to the study of star sapphire because asterism results from light reflected by oriented internal features. Their form, composition, orientation and associations can also 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 star 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.