Thai Sapphire Inclusions

First Published: 7 September 2026

Thai Sapphire Inclusions

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

In yellow and orange sapphires from Chanthaburi, Thailand, a thin layer of iron-rich silk is often found just under the table.
Angular dislocation needles interesect in this sapphire from Thailand.
In yellow sapphire from Chanthaburi, Thailand, a thin layer of iron-rich silk is typically found in green layers on the skin of the crystal. After cutting, it is commonly seen just under the table and/or culet.
In yellow sapphire from Chanthaburi, Thailand, a thin layer of iron-rich silk is typically found in green layers on the skin of the crystal. After cutting, it is commonly seen just under the table and/or culet. In this example we can also see a series of fine boehmite needles on the left.
A small crystal with an iridescent thin-film decrepitation halo surrounding it. When a crystal is heated (either by a magma or artificially by human intervention), it expands. Tension is often relieved by a fissure in the weakest direction, the basal plane.
A small crystal with an iridescent thin-film decrepitation halo surrounding it. When a crystal is heated (either by a magma or artificially by human intervention), it expands. Tension is often relieved by a fissure in the weakest direction, the basal plane.
A melted crystal with a frozen gas bubble inside is suspended over a backdrop of partially dissolved silk which displays “inkspot” internal diffusion.
This pale sapphire has been soaked in blue dye to deepen its color. Under the microscope one can clearly see the blue stains in the fissures.
An iridescent fissure surrounds a small crystal in this basaltic sapphire from Bo Ploi, Thailand. When an included crystal such as this is heated, it expands, producing pressure on the host. The easiest release of that pressure is generally in the basal plane, producing a flat “discoid” fissure such as this.
Thin layer of iron-rich silk in a yellow sapphire from Chanthaburi, Thailand. This type of silk is typically found in green layers on the skin of the crystal and thus after cutting, is generally found just under the table and/or culet.
Thin layer of iron-rich silk in a yellow sapphire from Chanthaburi, Thailand. This type of silk is typically found in green layers on the skin of the crystal and thus after cutting, is generally found just under the table and/or culet.
Green color zone in a yellow sapphire from Chanthaburi, Thailand. This type of zoning is typically found on the skin of the crystal and thus after cutting, is generally found just under the table and/or culet. Careful examination often reveals thin patches of iron-rich silk in these green zones.

Thai sapphire inclusions may include mineral crystals, 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 Thai origin.

Thai Sapphire Inclusion Photomicrographs

The Hyperion Thai sapphire gallery includes microscopic features documented in sapphires from Thailand and the Thailand–Cambodia border region. Each entry is accompanied by descriptive information and, where available, references to the gemological literature.

What Inclusions Can Reveal About Thai 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 Thai origin.

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