
Recently, the authors examined a 2.57 ct natural type Ia diamond with some interesting inclusion features. This round brilliant stone with I-color and I1 clarity contained interesting transparent and yellow crystal inclusions (see above). The transparent crystal resembled the profile view of a faceted round brilliant diamond. Within the “crown” of this ghostly faceted transparent crystal, a yellow crystal was also observed. Although the crystal’s identity was unconfirmed, it showed a morphology resembling that of an octahedral rough diamond. Similar inclusions have been documented previously (Summer 2022 G&G Micro-World, pp. 227–228; Spring 2024 G&G Micro-World, pp. 81–82). No obvious strain was observed when the diamond was examined through crossed polarizing filters. These unusual inclusions—resembling a miniature faceted diamond and a yellow octahedral rough diamond—are “knot” commonly observed in the laboratory.
Ravikumar Sharma is an associate diamond grader, and Krishna Sagar is a training specialist, at GIA in Mumbai. Sally Eaton-Magaña is senior manager of diamond identification at GIA in Carlsbad, California.

Recently, the authors examined a 2.57 ct natural type Ia diamond with some interesting inclusion features. This round brilliant stone with I-color and I1 clarity contained interesting transparent and yellow crystal inclusions (see above). The transparent crystal resembled the profile view of a faceted round brilliant diamond. Within the “crown” of this ghostly faceted transparent crystal, a yellow crystal was also observed. Although the crystal’s identity was unconfirmed, it showed a morphology resembling that of an octahedral rough diamond. Similar inclusions have been documented previously (Summer 2022 G&G Micro-World, pp. 227–228; Spring 2024 G&G Micro-World, pp. 81–82). No obvious strain was observed when the diamond was examined through crossed polarizing filters. These unusual inclusions—resembling a miniature faceted diamond and a yellow octahedral rough diamond—are “knot” commonly observed in the laboratory.
Ravikumar Sharma is an associate diamond grader, and Krishna Sagar is a training specialist, at GIA in Mumbai. Sally Eaton-Magaña is senior manager of diamond identification at GIA in Carlsbad, California.




