Crystalline osmium – the scarcest and densest platinum-group metal (PGM) globally – attracts more long-term opportunities for investors than diamonds, says precious metals refiner Gauteng Refinery manager Michele Beaumont.

“Market observers expect an unprecedented increase in value in the coming years. The ‘for profit’ world collectors of crystalline osmium consider the metal a secret,” notes Beaumont.

She explains that osmium is not easily refined owing to it being a complex PGM with eight oxidation states.

The metal forms compounds with oxidation states ranging from -2 to +8, with +8 oxidation exhibited in osmium tetroxide – a toxic compound when powdered osmium is exposed to air.

Additionally, two particular osmium compounds have major applications: osmium tetroxide – for staining tissue in electron microscopy and for the oxidation of alkenes in organic synthesis – and the nonvolatile osmates for organic oxidation reactions.

Osmium tetroxide is used to detect fingerprints and stain fatty tissue for microscope slides, while platinum-osmium 90/10 alloy is used in implants such as pacemakers and replacement valves.

Osmium is also used to produce hard alloys with other PGMs for fountain pen tips, instrument pivots and electrical contacts. Crystalline osmium can be bought as crystal bars or billet rings and is nontoxic in this form.

The metal remains lustrous at high temperatures and has a low compressibility and high melting-point of 3 033 ºC.

Further, while the Gauteng Refinery has witnessed an ongoing demand for the refining of osmium, sourcing osmiridium – an alloy of osmium and iridium – remains challenging, owing the metal being a scarce, exhaustible resource.

Beaumont notes that the significant demand can be attributed to the Gauteng Refinery being one of only three global refineries that refine osmium.

“The search for osmiridum, and the refining thereof, is ongoing to meet the demands of investment and practical applications. Our aim has always been to create a centre of excellence for PGMs refining globally. We also aim to fulfil new and unique PGMs demand as it is created in an ever-evolving world,” concludes Beaumont.