Hematite Crystals in Diamond

Abadie Ludlam, Tingyen Yeh, and David Kondo

A 1.51 ct G-color diamond with I₂ clarity recently caught the authors’ attention due to several brownish orange inclusions. These tiny crystals, only a few nanometers in size, were concentrated along two fractures in the stone (see above). They were identified using Raman spectroscopy as hematite (Fe₂O₃). Although it is common to find oxide staining within fractures in diamond, crystalline oxide inclusions such as these are a rarity. The concentration of the hematite crystals along the cracks suggests that, rather than being syngenetic inclusions, these are secondary (epigenetic) minerals. They likely precipitated inside the fractures when the diamond interacted with fluids while being stored in the crust. This rare sight offers a glimpse into the long and unique journey each diamond takes to the earth’s surface.