GIA Uncovers Rare Star-Shaped Inclusions in Large Diamonds

Weighing 8.14 and 8.57 carats, these diamonds are notable not only for their size but also for their preserved natural forms, as highlighted in the summer 2024 edition of GIA’s "Gems & Gemology."

The diamonds, known as asteriated or "star" diamonds, showcased light brown cloud inclusions, a phenomenon caused by high concentrations of hydrogen and nickel during the stones' formation. GIA noted that these inclusions, which can also contain graphite, are relatively rare and make these diamonds particularly unique.

The 8.14-carat diamond displayed an intriguing mix of natural and processed features. One side of the diamond retained its rough form, with natural surfaces showing brown radiation stains—evidence of exposure to natural alpha irradiation followed by annealing deep within the Earth. The other side of the diamond was sliced to reveal the star-shaped inclusion pattern underneath.

The 8.57-carat diamond, in contrast, was polished with bruted edges, but still maintained its characteristic star-shaped inclusion. Both diamonds have undergone a process called resorption, where natural fluids or magma partially dissolve the stone, leading to a rounded shape. Despite this process, the diamonds preserved much of their original form.

While asteriated diamonds occasionally make their way to GIA’s labs, these two are exceptional due to their significant size and the well-preserved natural characteristics that offer a glimpse into their geological history.

The discovery of these star-shaped inclusions adds to the allure and mystery of natural diamonds, providing valuable insights into the conditions under which they formed millions of years ago. These diamonds not only captivate with their beauty but also with the scientific stories they tell, making them rare treasures in the world of gemology.