Corundum is found in many disparate locations. Similarly, the morphology of impurity clouds in corundum can vary between localities, from the ultrafine, wide-banded clouds of Kashmir to the layered geometric clouds of Madagascar. Although rarely endemic, they can be used by gemologists to support geographic origin determinations.
The author recently examined a 4.00 ct Sri Lankan blue sapphire from GIA’s colored stone reference collection. The stone exhibited groups of intersecting needles, fingerprints, and a twinning plane. Additionally, particle clouds with a unique interlocking triangular pattern were found under fiber-optic illumination (see above). This is the first time the author has observed this pattern in a sapphire from Sri Lanka.
Titapa Tanawansombat is a senior analytics technician at GIA in Bangkok.
Corundum is found in many disparate locations. Similarly, the morphology of impurity clouds in corundum can vary between localities, from the ultrafine, wide-banded clouds of Kashmir to the layered geometric clouds of Madagascar. Although rarely endemic, they can be used by gemologists to support geographic origin determinations.
The author recently examined a 4.00 ct Sri Lankan blue sapphire from GIA’s colored stone reference collection. The stone exhibited groups of intersecting needles, fingerprints, and a twinning plane. Additionally, particle clouds with a unique interlocking triangular pattern were found under fiber-optic illumination (see above). This is the first time the author has observed this pattern in a sapphire from Sri Lanka.
Titapa Tanawansombat is a senior analytics technician at GIA in Bangkok.
