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Platinum football – created by nature

Platinum football – created by nature

Published: 28 November 2022

"The FIFA World Cup has just started when I was busy in the lab investigating a heavy mineral concentrate from a chromitite sample, and found this fantastic example of an euhedral grain of sperrylite (PtAs2) – resembling a football but only 50 µm in size”, says PhD student Matías Garcia Tudela from Applied Geochemistry.

The platinum-group mineral (PGM) in the image shows a perfect cubo-octahedral morphology as sperrylite crystallizes in the isometric crystal system. Sperrylite can be found associated to several geological environments but is mainly found in magmatic (ultramafic-mafic intrusions) as well as in alluvial deposits related to these intrusions. The “sperrylite football”, in the size of a human´s hair diameter, was discovered in a heavy mineral concentrate obtained via hydroseparation of a crushed and sieved chromitite sample from the Cabo Ortegal Complex (Spain).

What is hydroseparation?

The hydroseparation process is a water-based and hence environmentally friendly method to obtain heavy mineral concentrates following the physical principles of the “stokes-law”. The process includes pulses of water that simulate waves from a natural beach placer deposit. LTU has such a hydroseparation facility within the quantitative target mineralogy (QanTmin) laboratories at Applied Geochemistry. After the successful separation, the sperrylite grain was investigated via scanning electron microscopy (SEM) at the QanTmin labs.

Matias Garcia Tudela

Matias Garcia Tudela, PhD Student

Phone: +46 (0)920 491784
Organisation: Applied Geochemistry, Geosciences and Environmental Engineering, Department of Civil, Environmental and Natural Resources Engineering