Chromium
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40 free Chromium trivia questions with answers — science & nature quiz, new questions added Oct 2026.
Chromium is the element behind the mirror shine on a bike or a bathroom tap, but the pure metal is only half the story. Its compounds come in some of the brightest shades in chemistry, which is why it turns up in gemstones, artists' paints and even a few famous court cases. This quiz turns the best fun facts about chromium into 40 multiple-choice questions. They cover how the element got its name, which family of the periodic table it belongs to, who first isolated it, where it is mined, and the surprising places it hides in everyday life, from kitchens to skyscrapers. It is pitched at curious adults, students and kids revising the periodic table, and quiz hosts who want a science round with stories attached. Every answer comes with a short explanation.
30 of 40 questions with answers and explanations. Play the quiz
Q 01Traces of chromium turn clear crystals of aluminum oxide into which precious gemstone?
Ruby
Ruby owes its red to chromium atoms that take the place of about one in a hundred aluminum atoms. The same crystal without chromium is called sapphire.
Q 02Trace amounts of chromium give which gemstone, a variety of the mineral beryl, its famous green?
Emerald
Emerald is beryl tinted by chromium or sometimes vanadium, so the metal that makes one famous gem red makes another green.
Q 03Chrome yellow, a chromium pigment, was chosen in 1939 as the paint for which North American vehicles?
School buses
School buses wore a shade first officially named National School Bus Chrome. Its lead chromate pigment was later replaced because it is toxic.
Q 04Which 2000 film stars Julia Roberts exposing chromium-poisoned groundwater in Hinkley, California?
Erin Brockovich
Erin Brockovich tells the true story of a case settled for $333 million in 1996, and it won Julia Roberts the Academy Award for Best Actress.
Q 05Chromium on 2,200-year-old bronze weapons at which Chinese site was long mistaken for an ancient protective coating?
Terracotta Army
Terracotta Army weapons were thought to have been chromium-coated to stop decay, until research in 2019 showed the metal was contamination from nearby lacquer.
Q 06Theodore Maiman used chromium atoms in a synthetic crystal to build the world's first working what?
Laser
Laser light first shone on May 16, 1960, at Hughes Research Laboratories, where the chromium in Maiman's crystal gave off a deep red beam.
Q 07Iron alloys with at least 10.5 percent chromium go by which name, familiar from sinks and cutlery?
Stainless steel
Stainless steel is protected by an invisible film of chromium oxide that forms on its surface and can heal itself.
Q 08Chromium salts are used in making roughly 85 to 90 percent of the world's supply of which material?
Leather
Leather is mostly chrome-tanned, with chromium locking the collagen fibers of a hide together. Tanners borrowed the idea after 1840 from the treatment of surgical gut stitches.
Q 09Chromium is also the name of an open-source web browser project led by which technology company?
Google leads the Chromium project, whose code underpins not only Chrome but also Microsoft Edge, Opera and Samsung's browser.
Q 10Chromium takes its name from a word meaning color in which ancient language?
Greek
Greek chroma, meaning color, was chosen because chromium compounds range from red and orange to yellow, green and violet.
Q 11Chromium compounds come in vivid reds and greens, but what does the pure metal look like?
Steely gray
Steely gray, hard and brittle, chromium takes a high polish that reflects almost 70 percent of visible light.
Q 12Chromium belongs to which family of elements, found in the middle block of the periodic table?
Transition metals
Transition metals fill groups 3 to 12 of the table, and chromium is the first member of group 6.
Q 13Which Art Deco skyscraper in New York, completed in 1930, wears a crown of chromium-rich Nirosta steel?
Chrysler Building
Chrysler Building cladding was the first American use of the German alloy, which is 18 percent chromium and also covers the needle and window frames.
Q 21Crocoite, the orange-red mineral in which chromium was found, is the emblem of which Australian state?
Tasmania
Tasmania's old mines at Dundas have produced exceptional crocoite crystals, a lead chromate once ground up as a yellow paint pigment.
Q 22Harry Brearley created rustless chromium steel in 1913 while seeking better gun barrels in which English city?
Sheffield
Sheffield was already famous for cutlery, and a local cutlery maker who tried Brearley's alloy gave it the name that stuck.
Q 23Chromium heads group 6 of the periodic table, which also includes which metal with the chemical symbol W?
Tungsten
Tungsten sits two rows below chromium and has the highest melting point of any metal, 3,422 degrees Celsius.
Q 14Nichrome, the wire that glows inside toasters, is an alloy of chromium and which other metal?
Nickel
Nickel makes up about 80 percent of classic nichrome, which Albert Marsh patented in 1906 and which is the oldest documented alloy for electric heating.
Q 15Vincent van Gogh used chrome yellow, a chromium pigment that slowly browns, in which series of paintings?
Sunflowers
Sunflowers studies show he mixed several shades of chrome yellow, a lead chromate pigment first made in the early 1800s.
Q 16Which country, home to the Bushveld Complex, has long been the world's largest producer of chromium ore?
South Africa
South Africa has layers in its Bushveld Igneous Complex that are up to 90 percent chromite, the mineral mined for chromium.
Q 17Chromium dioxide, a magnetic compound, gave its name to premium 'chrome' versions of which music format?
Cassettes
Cassettes coated with chromium dioxide outperformed ordinary iron oxide tape. DuPont, which invented the manufacturing process, began selling the coating in 1968.
Q 18The mirror-bright chromium finish on car trim and taps is usually applied by which process?
Electroplating
Electroplating lays down a decorative chromium coat less than a thousandth of a millimeter thick. The process took off after an improved method arrived in 1924.
Q 19Chromium is the third-hardest element; only boron and which other element, in one crystal form, are harder?
Carbon
Carbon in the form of diamond tops the list. Chromium rates 8.5 on the Mohs scale, hard enough to scratch quartz and topaz.
Q 20Chromium supplements are sold for a suspected, though unproven, role in helping which hormone do its job?
Insulin
Insulin controls how the body stores sugar, fat and protein, but European regulators concluded in 2014 that chromium has not been shown to be an essential nutrient.
Q 24Chromite deposits near which American port city made the United States the top chromium supplier until 1848?
Baltimore
Baltimore businessman Isaac Tyson, who first mined the ore on his own farm, came to hold a virtual monopoly on the world's chromium minerals.
Q 25Chromoly steel, prized for bicycle frames and roll cages, blends chromium with which other element?
Molybdenum
Molybdenum and chromium are the alloying elements of the 41xx family of steels, which also go into gas cylinders, firearm parts and flywheels.
Q 26Armies paint vehicles with a chromium oxide pigment because it reflects infrared light much like what?
Green leaves
Green leaves and chromium oxide reflect infrared in the same way, so the paint keeps a camouflaged vehicle matched to the plants around it.
Q 27Chromium gives which gem its shift from green in daylight to red by lamplight?
Alexandrite
Alexandrite honors the future Emperor Alexander II. Its chromium absorbs yellow light so strongly that the stone follows whichever of green or red its lighting favors.
Q 28Traces of chromium give 'imperial' stones, the most valuable variety of which gem, their intense green?
Jade
Jade of the imperial kind is jadeite with a little chromium in its crystals, while extra iron instead turns the stone a much darker green.
Q 29The chromium-based Phillips catalyst is used to make about half the world's supply of which plastic?
Polyethylene
Polyethylene is the most-produced synthetic polymer of all, and a catalyst of chromium oxide on silica gel turns out roughly half of it.
Q 30CCA, a preservative that tints outdoor timber green, combines chromium with a second metal and which poison?
Arsenic
Arsenic is the reason American regulators and the lumber industry agreed in 2003 to stop using CCA-treated wood for decks, fences and playground equipment.