Sapphire Inclusions

First Published: 7 September 2026

Sapphire Inclusions

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

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.
The shiny, melted appearance of this crystal and the fingerprint surrounding it suggest that their Madagascar sapphire host was heated.
Small “frozen” gas bubbles trapped in place inside negative crystals provide evidence that a stone has been heated, as seen in this example in a basalt-related sapphire.
Laser-Induced-Breakdown-Spectroscopy (LIBS) is used by some gem labs to test for beryllium. Unlike Laser Ablation Inductively Coupled Plasma Mass Spectroscopy (LA-ICPMS), the surface is actually melted (rather than ablated), producing the circular rippled mark we see in the center of the girdle on this stone.
Undissolved rutile silk intersects under the table of this untreated Sri Lanka sapphire.
Undissolved rutile silk intersects under the table of this untreated Sri Lanka sapphire.
Small snowflake-like inclusions are a common feature in untreated Madagascar sapphire.
Here four small round marks can be seen on the girdle, indicating that the stone has been analyzed by LA-ICP-MS (Laser Ablation Inductively Coupled Plasma Mass Spectrometry), which allows for chemical analysis of the stone.
Resembling a large insect, this crystal with a discoid fissure was found in a heat-treated padparadscha sapphire from Madagascar.
Some Madagascar sapphires contain fine needles of what is probably rutile, as shown here.
One crucial difference between Kashmir sapphires and those from Madagascar or Sri Lanka is that Kashmir sapphires almost never contain yellow staining in their fissures, while such epigenetic stains are common in Madagascar and Sri Lankan stones. The image here shows such a yellow epigenetic stain a Kashmir-like blue sapphire from Madagascar.
Some Madagascar sapphires feature thin “lace” or “doily” like inclusions that form in a lathe-like pattern. These are often confused with similar “snowflake” like inclusions in Kashmir sapphire.

Search the Complete Hyperion Database

Sapphire inclusions may include mineral crystals, rutile silk, healed fissures, fluid inclusions, negative crystals, color zoning and other features formed during or after crystal growth. Such features are important to gemologists because they can provide evidence useful in identifying sapphire, understanding its geological history, recognizing treatment and, in some cases, determining geographic origin.

Sapphire Inclusion Photomicrographs

The Hyperion sapphire gallery includes microscopic features found in sapphires from major deposits around the world. Each entry is accompanied by descriptive information and, where available, references to the gemological literature.

What Inclusions Can Reveal About Sapphire

Inclusions are an important part of sapphire identification. Their form, composition, orientation and alteration can help gemologists distinguish natural sapphire from synthetic material, recognize evidence of heat treatment, and study the geological environment in which the sapphire formed.

Hyperion combines inclusion photomicrography with supporting gemological information so that individual features can be compared with documented examples from known sapphire deposits.

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.