Facts About Chromium
Chromium Uses, Resources, Supply, Demand and Production Information
Republished from a USGS Fact Sheet from September, 2010
What is Chromium?
Chromium, a steely-gray, lustrous, hard metal that takes a high polish and has
a high melting point, is a silvery white, hard, and bright metal plating on steel and
other material. Commonly known as chrome, it is one of the most important and
indispensable industrial metals because of its hardness and resistance to corrosion. But
it is used for more than the production of stainles steel and nonferrous alloys; it is also
used to create pigments and chemicals used to process leather.
Chromite, the only ore of chromium, was first discovered in the United States
sometime about 1808 on the farm of Isaac Tyson, Jr., just north of Baltimore, Md.
Scattered deposits of chromium minerals in an area of northeastern Maryland and
southeastern Pennsylvania were the source of nearly all of the chromium productsin
the world between 1828 and 1850. Currently, the only domestic commercial chromium
supply source isfrom recycling, although the United States does have small chromite
resources, primarily in Oregon. The Stillwater complex of Montana also hosts chromite
resources associated with platinum and nickel resources.
How Do We Use Chromium?
Chromium is critical in the manufacturing of stainless steel. Most stainless steel contains about 18 percent
chromium; it is what hardens and toughens steel and increases its resistance to corrosion, especially at high temperatures.
Because stainless steel does not rust and is easily sterilized, it is a part of many items we use in our daily lives. Some of the most
recognizable of these items include kitchen appliances, food processing equipment, and medical and dental tools.
Many of the decorations on automobiles, such as ornaments, trim, and
hubcaps, are chromium plated. Chromium in superalloys (high-performance alloys)
permits jet engines to operate in a high-temperature, high-stress, chemically oxidizing
environment. On U.S. roadways, chromium pigments are used to make the yellow lines
that indicate traffic lanes. Chromium-containing pigments find their way into a variety
of beauty products. Chromite is used in high-temperature applications, such as blast
furnaces and molds for firing bricks, because it retainsstrength at high temperature.
Chromium is also vital for good health. Insufficient amounts result in glucose
intolerance in humans. Organ meats, mushrooms, wheat germ, and broccoli are all good
dietary sources of chromium.
Where Does Chromium Come From?
Chromite, an oxide of iron, magnesium, aluminum, and chromium, is the only ore
mineral of chromium. In nature, chromite deposits are generally of two major types:
stratiform (layered) and podiform (pod shaped). Both types are associated with ultramafic
igneous rocks. The world's largest stratiform chromite deposits are found in South
Africa, in what is known as the Bushveld complex. This is a layered igneous intrusion
containing more than 11 billion metric tons of chromite resources. Podiform deposits are
found in layered igneous sequences that developed in oceanic crust below the sea floor.
We can now access these resources where parts of the ocean floor have been pushed
over continental rocks by tectonic forces. In the United States, podiform deposits are
scattered along the Pacific Coast from the Kenai Peninsula in southern Alaska to southern
California and along the Appalachian Mountains from northern Vermont to Georgia.
Chromium: Worldwide Supply and Demand
The world's production (supply) and consumption (demand) of chromium have
been influenced by the global market, as demand for mineral commodities,
including chromium, has increased. Chromium istraded on the world
market in the form of ferrochromium, an iron-chromium alloy.
The price of ferrochromium reached historically high levels
in 2008 and then declined in 2009 with a weakening world
economy. During the same time period, China'srole as a
chromium consumer has grown with its expanding stainless
Ferrochromium production is an electrical energy-intensive
process. Much of the electrical power currently produced is
coal based, a carbon dioxide gas-producing process that is
under consideration for regulation because of its impact on
climate. These factors suggest that the electrical energy cost of
ferrochromium production will rise in the future.
Ensure Future Chromium Supplies
World chromium reserves, mining capacity, and ferrochromium production capacity are largely concentrated
in the Eastern Hemisphere. Because there is no viable substitute for chromiumin the production of stainless
steel and because the United States has small chromium resources, there has been concern about domestic supply
during every national military emergency since World War I. In recognition of the vulnerability of lengthy supply
routes during military emergencies, chromium (in various forms, including chromite ore, chromiumferro alloys,
and chromium metal) has been held in the National Defense Stockpile since before World War II. Since 1991,
however, changes in national security considerations have resulted in reduced stockpile goals, and inventories are
being sold. At the current rate, it is estimated that these stockpiles will be exhausted by 2015. In 2009, recycled
chromium from stainless steel scrap accounted for 61 percent of U.S. chromium apparent consumption,
making recycled material the only domestic commercial chromium supply source.
To help predict where future chromium supplies might be located, USGS scientists study how and
where identified chromium resources are concentrated in the Earth's crust and use that knowledge to
assess the likelihood that undiscovered chromium resources exist. Studies of the distribution of podiform
chromite depositsin ultramafic rocks in California and Oregon have helped to refine techniques used to
estimate undiscovered chromium resources. These kinds of USGS studies provide unbiased scientific
information to decision makers responsible for the stewardship of Federal lands, as well as data
required to better evaluate mineral resource availability in a global context.
Mineral resource assessments are dynamic. Because they provide a snapshot that reflects
our best understanding of how and where resources are located, the assessments must be updated
periodically as better data and concepts are developed. Current research by the USGS involves
updating mineral deposit models and mineral environmental models for chromium and other
important nonfuel commodities and improving the techniques used to assess for concealed
mineral resource potential. The results of this research will provide new information to decrease
uncertainty in future mineral resource assessments.
Find it on Geology.com
More from Geology.com
|100+ Gems - Photos of over 100 beautiful gems ranging from the popular to the obscure.
|Meteorites - Rocks that were once parts of planets or large asteroids.
|Free Google Earth software allows you to browse seamless world satellite images. Free.
|Rhodonite - a manganese silicate used as a minor ore of manganese and as a gemstone.
|School bus yellow, originally called chrome yellow for the chromium pigment, was
adopted for use on school buses in North
America in 1939 because black lettering on the yellow buses is easy to see in the
semidarkness of early morning. Image from commerce.gov.
|The Gateway Arch in St. Louis, Mo., covered with a stainless steel skin made with chromium, is 630 ft (192 m) tall and 630 ft (192 m) from leg to leg. Image © iStockphoto / Crackerclips.
||Did You Know? The name chromium is derived from the Greek word chroma, meaning color, capturing the fact
that many of its compounds are intensely colored.
||Did You Know? Trace amounts of chromium can be detected in precious gemstones, such as in rubies or
emeralds. Image © iStockphoto / SunChan.
||Did You Know? In early 19th century Britain, Princess Charlotte used ocher paint made from chromite - derived
chemicals on her carriage. The same color is seen on cars and cabs in the United States today. Image © BLS.gov.
|A specimen of chromite, the only ore of chromium, from the Transvaal area of South Africa. Specimen is approximately 4 inches (10 centimeters) across.
|Chromite Production and Reserves
||2011 Mine Production
||2012 Mine Production (estimated)
The values above are estimated chromite production and reserves in thousands of metric tons. Data from USGS Mineral Commodity Summaries.