Platinum is one of the most valuable metals on Earth. Its name originates from the Spanish word “platina” or little silver. The Platinum Group Elements (PGEs) can often be found together in nature. These metals include platinum, rhodium, ruthenium, palladium, osmium and iridium. Modern platinum uses include jewelry, catalytic converters, manufacturing silicones, increasing computer storage and use in flat-panel displays. Rocks containing platinum grains tend to be quite small, and the platinum itself is rarely visible. Platinum often requires laboratory analysis for identification.
TL;DR (Too Long; Didn't Read)
Platinum represents one of the rarest metals on Earth. Seldom occurring on its own, it exists with other metals in the Platinum Group Elements (PGEs): rhodium, ruthenium, palladium, osmium and iridium, and occasionally alongside gold and diamonds. Platinum can be found in alluvial placer deposits in flakes or in small grains. Positive identification often requires laboratory analysis.
Most PGEs originate in magnetic ore deposits. These formed as a result of magma cooling and crystallizing into sulfide globules. Magma formed various intrusions into shallow parts of the earth’s crust. PGEs can be therefore be found among mafic and ultramafic volcanic (igneous) rocks. Platinum shines with a silvery color, but it does not tarnish like silver. It can, however, corrode via halogens, sulfur and cyanides.
Platinum is rarely found on the Earth’s surface and is in fact 30 times rarer than gold. Sources for ore rocks often exist in areas of stream flow in the form of placer deposits. In South America, pre-Columbian civilizations found platinum intermixed with gold in river deposits. The largest platinum deposits reside in Russia, South Africa and Zimbabwe, with smaller deposits in Canada and the United States. In South Africa, where the greatest mine production occurs, the mineral cooperite represents a chief source of platinum. The geological structure for the ore in South Africa is an intrusion called the Bushveld Complex. Platinum also coexists with diamonds. The J-M Reef ore body in Montana contains mostly copper and nickel, with low platinum content as a byproduct. Gravel deposits in Alberta, Canada, provide a placer source for platinum in certain rivers, where it coincides with gold and other minerals. Platinum flakes can be recovered through gravel washings, shaking tables and other methods. Generally, platinum grains require microscopy for identification from alluvial deposits. The mineral sperrylite, in nickel deposits, also provides a source of platinum in Ontario.
The Importance of Platinum
Platinum serves the modern world in far greater capacity than as just beautiful jewelry. It can be used for coating jet or missile cones to withstand high heat, it can be used for laboratories, and it is used in electrical contacts. Platinum provides a catalyst for making sulfuric acid, nitric acid, silicone and benzene. It is used for converting methyl alcohol to formaldehyde. Platinum aids in pollution control as it comprises part of the catalytic converters in many vehicles. In electronics, platinum functions in the construction of computer hard drives and LCDs. Platinum is also used to produce terephthalic acid for polyester fabric and plastic containers. Because of its lack of toxicity, platinum and its alloys can be used in pacemakers and dental fillings, and be used in chemotherapy.
While platinum proves difficult to find and identify, with rare economic deposits, it serves as a crucial mineral for modern technology and aiding the environment.
- Carnegie Institution Science: Diamonds Reveal Deep Source of Platinum Deposits
- USGS: Platinum-Group Metals
- USGS: Platinum-Group Elements — So Many Excellent Properties
- USGS: 2015 Minerals Yearbook Platinum-Group Metals [Advance Release]
- Los Alamos National Laboratory: Periodic Table of Elements: Platinum
- Royal Society of Chemistry: Periodic Table: Platinum
- Alberta Energy and Utilities Board: Gold, Platinum and Diamond Placer Deposits in Alluvial Gravels, Whitecourt, Alberta
About the Author
J. Dianne Dotson is a science writer with a degree in zoology/ecology and evolutionary biology. She spent nine years working in laboratory and clinical research. A lifelong writer, Dianne is also a content manager and science fiction and fantasy novelist. Dianne features science as well as writing topics on her website, jdiannedotson.com.