The Cost, Characteristics, and Uses of Osmium
Osmium (Os) is one of the platinum group metals (PGMs), along with iridium (Ir), palladium (Pd), platinum (Pt), rhodium (Rh), and ruthenium (Ru). Its atomic number is 76, and its atomic weight is 190.23. As of 2018, it sells for $400 per troy ounce (about 31.1 grams), and that price had held steady for more than two decades, according to Engelhard Industrial Bullion prices.
Discovered in 1803 by British chemist Smithson Tennant, osmium has the highest density among naturally occurring elements at 22.57 grams per cubic centimeter. It also is extremely rare. Its abundance of 0.0018 parts per million in the earth's crust is significantly less than gold's 0.0031 parts per million, according to metalary.com, and less than a ton is produced each year. It typically is found as an alloy in platinum ores. Osmium is most abundant in Canada, Bulgaria, and Turkey, according to miningoilandgasjobs.com.
It is a hard and brittle metal that produces the foul-smelling and poisonous osmium tetroxide (OsO4) when it oxidizes. These traits combined with its high melting point make for poor machinability, meaning it is difficult to reform the metal into specific shapes.
Osmium is not typically used by itself but instead is used as one part of hard metal alloys. According to Jefferson Lab, its hardness and density make it ideal for devices that need to restrict wear from friction. Common items that might include alloys containing osmium are pen tips, compass needles, record player needles, and electrical contacts.
Quite possibly more useful than osmium is osmium tetroxide, despite its toxicity. According to metalary.com, it can be used to stain biological samples and is very effective at improving image contrast. It also has been used as part of a solution injected into arthritic joints to help destroy diseased tissue. Additionally, the compound is highly reflective, according to metalary.com, and has been used in mirrors for UV spectrometers. Significant precautions must be taken, though, when handling osmium tetroxide in a laboratory setting.
Osmium can be stored in cool, dry conditions if proper precautions are taken. It should not come into contact with oxidizing agents, ammonia, acids, or solvents, and it should be stored tightly inside a container. Any work with the metal should be done in a well-ventilated area, and contact with the skin or eyes should be avoided.
The market price of osmium has not changed in decades, primarily because little change has occurred in supply and demand. In addition to so little of it being available, osmium is difficult to work with, has few uses, and is a challenge to store safely because of the toxic compound it produces when it oxidizes. The bottom line is that it has limited market value and is not much of an investment option.
While the price of $400 per troy ounce has remained steady since the 1990s, inflation since that time has led to the metal losing about one-third of its value in the two decades prior to 2018.