Fish-Like Inclusion in Fancy Yellow
It is always a pleasant surprise to find a new and interesting inclusion during routine observation. But an inclusion that reminds us of a particular shape, an effect known as pareidolia (Winter 2007 Lab Notes, pp. 363–364), is a geologic wonder.
The New York laboratory recently received a natural yellow (graded as Fancy yellow) “Cape” 0.51 ct rectangular faceted diamond exhibiting such a feature. Examination of the stone revealed a series of table-reaching fractures and clouds that seemed to form the outline and scale-like detail of a fish (pictured at top). The inclusion is large in relation to the stone, encompassing nearly 75% of the table.
Nearly all fractures in diamond result from the interaction among multiple cleavage directions (The MicroWorld of Diamonds, Gemworld International, 2000, p. 97). While often detrimental to the value of a stone, this inclusion serves as a useful identifier, and such findings help keep the study of gems enjoyable.