Known as "stainless steel." When alloyed with iron and nickel, it produces an alloy known as "nichrome" which is Image copyright iStockphoto / 2windspa.Ĭhromium is a metal used to induce hardness, toughness, and chemical resistance in steel. The "chrome" means chromium was used as an ingredient. Uses of Chromite and Chromiumĭid You Know? School buses and yellow lines on highways are often painted with "chrome yellow" paint. These deposits are sometimes rich enough and large enough that they can be mined for chromite. This causes it to be selectively transported and deposited by wave and current actions, concentrating it in certain locations at streams andīeaches. Second, chromite has a higher specific gravity than other minerals In the weathering zone above chromite-rich rocks. That causes it to be concentrated in residual soils that form The more weathering-resistant minerals of peridotite. Two facts allow these chromite sands to occasionally contain economic deposits of chromite. Heavy minerals, and returned to the environment. Beach sand rich in chromite and other heavy minerals is sometimes mined, processed to remove Image copyright iStockphoto / Anna Usova.Ĭhromite is found in beach sands derived from the weathering of chromite-bearing rocks and laterite soils that developed Inexpensive mineral collections are available in the Store. The best way to learn about minerals is to study with a collection of small specimens that you can handle, examine, and observe their properties. Of the solid solution series that has a significant Cr 2O 3 content. Geologists and metallurgists often consider "chromite" to be any member (Fe 3O 4), and magnesioferrite (MgFe 2O 4).īecause of the many different compositions in these solid solution series, Spinel (MgAl 2O 4), magnesiochromite (MgCr 2O 4), magnetite ThisĬomposition recognizes multiple solid solution paths between chromite and hercynite (FeAl 2O 4), Some mineralogists give a generalized chemical composition of (Mg,Fe)(Cr,Al) 2O 4 for chromite. Intermediate specimens can be rich in iron ((Fe,Mg)Cr 2O 4) or magnesium ((Mg,Fe)Cr 2O 4).įor convenience in communication, these minerals are often referred to collectively as "chromite." A solid solution series exists between the mineralĬhromite (FeCr 2O 4) and the isomorphous mineral magnesiochromite (MgCr 2O 4). Magnesium frequently substitutes for iron in chromite. Image copyright iStockphoto / ProArtWork. The red color of rubies, the pink of some sapphires, and the green color of emeralds are derived from chromium. Careful observations of hardness, streak, and specific gravity are required to distinguish these minerals in hand specimens.ĭid You Know? The color of many gemstones is derived from trace amounts of chromium. This can cause it to be confused with magnetite. With ultrabasic igneous rocks and metamorphic rocks such as serpentinite.Ĭhromite is sometimes slightly magnetic. The most important clue to identifying chromite is its association Luster, and a characteristic brown streak. Hand specimen identification of chromite requires a consideration of: color, specific gravity, Several properties must be considered to differentiate it from other Dark gray to black, rarely brownish blackįeCr 2O 4 with magnesium substituting for iron in significant amountsĬhromite can be challenging to identify.
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