Pictured at left is a sulfide, inclusion-bearing rough diamond from the Jwaneng Mine in Botswana. This optical photomicrograph shows the natural diamond growth surface. Below the surface and at the center is a brass-colored, hexagonal-shaped grain of iron sulfide surrounded by an irregular black rim. The rim is caused by internal fracture of the diamond on its ascent to the Earth's surface via explosive volcanism. Sulfide grains such as these are removed for sulfur isotopic analysis. National Science Foundation-supported geologists James Farquhar and Boswell Wing from the University of Maryland have found that tiny inclusions encased in diamonds preserve information about the cycling of material between the Earth's atmosphere, crust and mantle some 3 billion years ago.
Visit Website | Image credit: Jeff Harris, University of Glasgow, U.K.