History
In the jewelry world, osmium is considered a promising newcomer. However, the precious metal already has a centuries-old history.
Osmium was first discovered in platinum ore by the English chemist Smithson Tennant in 1804. In its raw form, osmium is a hard, brittle, blue-gray or blue-black powder and is one of the eight precious metals, being part of the platinum metals group. The name osmium – derived from the Greek word osme (smell) – comes from the noxious and foul-smelling tetroxide present in raw osmium. Because of this toxicity, osmium in its raw form should also not be purchased or traded by private individuals.
Osmium is chemically reactive and was first used as filament in light bulbs by the Osram company before it was later replaced by tungsten due to its rarity and the harmful component. The company name Osram, held to this day, derives from the combination of the names Os-mium and Wolf-ram (German for tungsten). Due to its low occurrence, there are still only a few possible applications for raw osmium today. Osmium alloys are used in vanishingly small quantities, for example in the manufacture of pacemakers, in special arthritis treatment, and artificial valves.
Crystallization
In 2014 following 40 years of research, Swiss scientists succeeded for the first time in crystallizing raw osmium in a flat structure, causing the metal to lose its toxicity and become completely safe. Today, about 160 steps are required to transform osmium into a standardized and certifiable form – a basic requirement for osmium as a tangible asset and for use in the luxury and jewelry industries. However, the exact process remains a well-kept secret of the Swiss. To date, no one else has been able to crystallize osmium in flat form without spikes and holes. This breakthrough triggered massive commercial interest in osmium. Because the crystallization of osmium is so complex, labor-intensive, and dangerous, osmium jewelry is among the most expensive and exclusive of all.
Crystalline osmium under a scanning electron microscope: The osmium crystals typically have a height of 200 to 300 micrometers. This corresponds to about one tenth of the diameter of a human hair.
Features
Osmium is an outstanding element: It has the highest density of all stable elements and compounds, is abrasion-resistant, has a high compression modulus and is a superconductor at low temperature. In its crystalline form, osmium also has the highest value density of all precious metals. For this reason – and because of its unique crystal structure – osmium is absolutely unforgeable. It reflects light instead of refracting it, resulting in osmium sparkling more than any diamond. Of all platinum metals, osmium has the highest melting point and the lowest vapor pressure. In addition, as a precious metal, crystalline osmium does not rust because it is inert and corrosion resistant. It is non-reactive and is therefore an ideal jewelry metal.
Occurrence
In its natural form (as crude osmium), osmium occurs in extremely small quantities in various parts of the world, for example in Canada, South Africa, the Urals, and South and North America. Unlike gold, however, no mines are operated specifically for osmium. Osmium is almost always associated with the other platinum metals, first and foremost platinum. Production therefore practically always takes place while mining other precious metals. The worldwide deposit of mineable osmium is estimated to be just about 1 cubic meter and thus about 20 tons, which means that all the osmium in the world would fit into a small car (which would then no longer be able to drive due to the weight of the load). All this makes the raw material the rarest stable element and – in its crystalline form – the most valuable precious metal in the world.
Forms
In general, osmium can be purchased in four different forms, which differ in their workability, counterfeit resistance, and toxicity.
Find a PDF here where we go into more detail about the different forms of osmium: