Inclusions in Sapphire [Sapphire Introduction Course 9]

For an experienced gemologist, the inclusion in the sapphire can be used as an important identification clue to judge:

• Is sapphire natural or synthetic

• Has the sapphire been processed

• Sapphire mining location/area (origin identification)

Inclusions of sapphires can provide clues to gem identification to explore what kind of geological environment the sapphire was formed in, thus making it possible to further determine the geographical origin of the sapphire. An inclusion, on the other hand, is the substance inside the gem: it may be formed before, during or after the formation of the sapphire, and the inclusion can be solid, liquid or gas. It's just that

Sheet-like inclusions in unheated Burmese sapphires. Photo: Michael Krzemnicki, SSEF

Above: Amphibole needle-like crystal in Kashmir sapphire. Below: Tourmaline inclusion in a Kashmir sapphire. Photo: Michael Krzemnicki, SSEF

Above: Cloud-like inclusions in Kashmir sapphires. Below: Fine-column zircon crystals in Kashmir sapphires that extend to the surface of the gemstone, which can be used for dating. Photo: Michael Krzemnicki, SSEF

Different growth zones ('blocks') common in sapphires from Madagascar. Photo: Michael Krzemnicki, SSEF

Above: Sapphire from Sri Lanka under a microscope. Below: Gas-liquid and graphite inclusions in Sri Lankan sapphires. Photo: Michael Krzemnicki, SSEF

Above: Color spots in heat-treated sapphires. Below: An atoll structure in heat-treated sapphires: stress cycles caused by the expansion of inclusions in sapphires due to high temperatures. Photo: Michael Krzemnicki, SSEF