A RARE and DESIRABLE Brazilian specimen: a gemmy, glassy and lightly frosted, 5 mm, octahedral diamond crystal nestled amongst conglomerate river pebbles from the famous Diamantina River of Minas Gerais. These alluvial diamonds, deposited into conglomerates over time, are the reason this region of Brazil was named after an old-time diamond rush! Ex. Ed Swoboda collection. He obtained them in Brazil 40-50 years ago.