Diamonds from Diamantina – MG, Brazil

A rare feature – hexagonal pitting

Diamonds occur in many colours, shapes, sizes and transparencies. Sometimes they just look like sand (well, expensive, very expensive sand, as a lowly 10 USD/carat stone is worth more than gold – currently hovering 1.200 USD/oz); or else diamonds may be broken (chips), dotted in the inside with other minerals, eroded or pitted at the surface, colourless, slightly tinted or, rarely, fancy (marked tints).

The rough diamonds in this parcel are from the Diamantina region (Jequitinhonha river) in Minas Gerais (Brazil). This is an historic diamond district, originally found and discovered in the early 17th century during Brazil’s colonial period. Diamonds in the area tend to have a greyish tint; alas, this is not their body color (as they would be extremely rare and expensive), just the color of a shallow coating probably due to radiation.

This photo illustrates a rare diamond feature caught by chance on camera. Note the focused diamond on the right hand side; it has a triangular shape (locally know has chapéu de frade). On the center of the diamond there is a depression of rare hexagonal shape, unlike trigons diamond’s characteristic inverted pyramidal pits.

Published by

Luís Chambel

Exploration & Research Mining Engineer, MSc Engineering Geology, MBA, PhD European Engineer -EUR ING; Euro Geologist - EURO GEOL

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