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50 free Gemstones trivia questions with answers — science & nature quiz, new questions added Aug 2026.
Gemstones are geology you can wear, and almost every famous one carries a story: a stone that powered the first laser, a crown jewel that is not what its name says, a museum heist solved by a tip-off, and a pigment so precious that painters saved it for the Virgin Mary. These 50 questions range across the precious four and the semi-precious crowd: what gives each stone its colour, where the finest ones are mined, how birthstones were standardised, which gems are grown in a lab, and the famous diamonds, sapphires and pearls that have passed through royal and rather less royal hands. Most are pitched for a pub table or a family quiz night, with a harder tier for collectors and jewellers. Play on your phone with instant answers and explanations, or print the set for a quiz night, a classroom or a jewellery-party icebreaker.
30 of 50 questions with answers and explanations. Play the quiz
Q 01Which purple stone, its Greek name meaning 'not drunk', was a 'cardinal' gem until Brazilian finds made it common?
Amethyst
Amethyst sat with diamond and the big coloured stones as one of five cardinal gems until the 18th century, when Brazil's huge deposits made it cheap. Anglican bishops still wear amethyst rings, a nod to the Apostles being 'not drunk'.
Q 02Which blue-violet gem, found in 1967 in the Mererani Hills, did Tiffany & Co. rename and launch in 1968?
Tanzanite
Tanzanite is the name Tiffany & Co. gave blue-violet zoisite in 1968, judging the mineral's real name too unappealing to sell. The whole supply comes from one deposit about 7 km long, and in 2002 it became December's newest birthstone.
Q 03Which aluminium-oxide mineral goes by one gem name when red and another in every other colour?
Corundum
Corundum gives the world two of the four precious stones: its chromium-red crystals and the sapphires of every other colour, blue included. The name comes from the Tamil word kurundam, and at 9 on the Mohs scale only diamond is harder.
Q 04Which word comes from 'elektron', the Greek for amber, because the rubbed resin takes a static charge?
Electricity
Electricity, electric and their relatives all descend from elektron, the Greek for amber, which bears a static charge when rubbed. Persian called the stone kah-ruba, 'straw-snatcher', and that word became the Arabic for electricity too.
Q 05Which gem, classed as a mineraloid because it has no crystal structure, did NASA announce in 2008 it had found on Mars?
Opal
Opal deposits on Mars were announced by NASA in late 2008, the same year a big new opal field turned up near Wegeltena in Ethiopia. Opal is hydrated silica with no crystal structure, so it counts as a mineraloid rather than a mineral.
Q 06The first working laser, built by Theodore Maiman in 1960, used a synthetic rod of which gem as its light source?
Ruby
Ruby, grown synthetically, was the gain medium in the laser Maiman fired at Hughes Research Laboratories on 16 May 1960. A xenon flashtube pumps the rod with light, and the chromium atoms that colour the crystal red do the lasing.
Q 07Which royal bride chose her own 12-carat oval sapphire ring from Garrard, the ring William gave Catherine in 2010?
Diana Spencer
Diana Spencer picked the ring herself in 1981: a 12-carat oval blue sapphire ringed by 14 diamonds in 18-carat white gold, made by Crown jewellers Garrard and like her mother's. William proposed with it in 2010.
Q 08Which mineral did the ancient Greeks call 'krystallos', thinking its clear form was ice frozen too hard to melt?
Quartz
Quartz was krystallos, from kryos, 'icy cold', because Theophrastus and others believed clear rock crystal was permanently frozen water, an idea Pliny the Elder still held. Every 'crystal' in English descends from that mistake.
Q 09A pearl is built up in layers of which iridescent material, the same stuff that lines a mollusc's shell?
Nacre
Nacre, better known as mother of pearl, is laid down by the same living process whether it coats the shell's interior or wraps an intruder into a pearl. It is calcium carbonate, mostly aragonite, deposited in concentric layers.
Q 10Which country, home to the Muzo mines, produced 47% of the world's emeralds in the decade to 2005?
Colombia
Colombia has long been the world's largest emerald producer, though its share has slipped for want of new finds and modern mining. Its mines also yield rare 'trapiche' emeralds, marked by ray-like spokes of dark impurities.
Q 11The 423-carat Logan Sapphire, the size of a chicken egg, came from which island, original home of the padparadscha?
Sri Lanka
Sri Lanka produced the Logan Sapphire, which Rebecca Guggenheim gave to the Smithsonian in 1960 set in a brooch ringed by 20 diamonds. The island's pink-orange padparadscha is the priciest of all the fancy-coloured sapphires.
Q 12Which pale-blue gem shares the beryl family with emerald, its largest known example being Brazil's Dom Pedro?
Aquamarine
Aquamarine shares the beryl family with emerald and heliodor, and is common enough to be the affordable one. The largest known, the Dom Pedro, was found at Pedra Azul in Minas Gerais, Brazil, in the late 1980s.
Q 13Which green gem, an August birthstone, turns up inside pallasite meteorites as well as in volcanic basalt?
Q 21Which pigment, ground from lapis lazuli, did Renaissance painters reserve for the Virgin Mary's clothing?
Ultramarine
Ultramarine, made by grinding lapis imported from the end of the Middle Ages, was used by Masaccio, Titian and Vermeer, and has even turned up in the dental tartar of medieval nuns, probably from licking their brushes.
Q 22Pliny the Elder claims which queen dissolved a pearl worth millions of sesterces in vinegar to win a dinner-party bet?
Cleopatra
Cleopatra pulled a stunt that works in chemistry as well as legend: pearls are mostly calcium carbonate, which reacts with the acetic acid in vinegar to give calcium acetate and carbon dioxide. Pliny tells the tale in his Natural History.
Q 23Moissanite, first found in 1893 in rock from Arizona's Meteor Crater, is a natural form of which compound?
Peridot
Peridot is gem-quality olivine, the magnesium-rich forsterite, and stones born in meteorites carry less lithium, nickel and zinc than volcanic ones. Gem-grade crystals are rare on Earth because olivine breaks down so readily at the surface.
Q 14Which January birthstone, really a family of minerals, is named for the pomegranate, whose red seeds it resembles?
Garnet
Garnet has been cut for gems and crushed for abrasives since the Bronze Age, and its species span 6 to 7.5 on the Mohs scale. Certain garnets serve as indicator minerals in the hunt for diamonds.
Q 15Diamond is not forever: at room temperature and pressure it is metastable and slowly turns into which form of carbon?
Graphite
Graphite is the stable form of carbon under everyday conditions, but diamond converts to it at a negligible rate, so the change is academic. In graphite the atoms bond in planes that slip past each other, which is why it is soft.
Q 16Which cut polishes a gem into a smooth dome instead of facets, the way to show a star or a cat's eye?
Cabochon
Cabochon, from the Middle French for 'head', was how every gem was finished before faceting was invented, and it is still the cut for opaque stones. The dome shows the star in a star sapphire that faceting would hide.
Q 17A diamond's rainbow flashes, which jewellers call 'fire', come from which optical property of the stone?
Dispersion
Dispersion, the splitting of white light into colours, is what the trade calls fire, and diamond has an unusually high value of it alongside its high refractive index. Early cuts like the rose barely showed it; the brilliant was built to.
Q 18Jet, the black stone Queen Victoria wore in mourning for Prince Albert, is a form of what?
Fossil wood
Fossil wood, squeezed over millions of years into lignite, the lowest rank of coal, is what jet is, mostly from trees akin to the Chilean pine. It became fashionable in the 1850s and gave English the phrase 'jet-black'.
Q 19Red 'precious' coral, the Corallium rubrum carved into jewellery since antiquity, grows mainly in which sea?
Mediterranean
Mediterranean waters are the main home of Corallium rubrum, which grows on dark rocky seabeds in the depths or in caves. Coral jewellery turns up in prehistoric European burials, and the material is too soft to facet, so it is cut as beads.
Q 20The Sar-i Sang mines, which have supplied lapis lazuli since the 7th millennium BC, lie in which modern country?
Afghanistan
Afghanistan's Badakhshan province supplied the lapis in Tutankhamun's funeral mask and served the ancient Persian and Mesopotamian civilisations, and its mines still dominate the trade. Sar-i Sang sits in the Kokcha River valley.
Silicon carbide
Silicon carbide crystals from the crater were first taken for diamonds by Henri Moissan, who only identified them correctly in 1904. Edward Acheson had already made the compound artificially in 1891, two years before the natural find.
Q 24Which Washington socialite bought the Hope Diamond from Pierre Cartier in 1911, curse stories and all?
Evalyn Walsh McLean
Evalyn Walsh McLean paid over $300,000 after Cartier's slow-burn presentation; the tales of a cursed origin were most likely invented in the early 1900s to add mystique and lift the price. Harry Winston bought it from her estate in 1949.
Q 25The 563-carat Star of India, stolen from New York's natural history museum in 1964, turned up months later where?
A Miami bus locker
A Miami bus locker gave up the uninsured Star of India in January 1965, when one of the thieves, seeking leniency, led police to it. The 1964 raid also took the Midnight Star and the Eagle Diamond.
Q 26The Regent Diamond, mined in India and cut in London, was mounted on the sword guard of which French ruler in 1801?
Napoleon
Napoleon redeemed the Regent in 1801 and had goldsmiths Odiot, Boutet and Nitot set it in his sword guard; by 1812 it sat on his two-edged sword. His second wife, Marie Louise, carried it off to Austria when he was exiled.
Q 27The 'modern' birthstone list most jewellers still use was adopted in August 1912 at a jewellers' meeting held where?
Kansas City
Kansas City hosted the National Association of Jewelers, now Jewelers of America, when it fixed the list that one author called 'nothing but a piece of unfounded salesmanship'. Tiffany had printed birthstone poems as early as 1870.
Q 28Which of jade's two minerals did China carve for millennia before Burmese jadeite arrived in quantity around 1800?
Nephrite
Nephrite, the white 'Hetian jade' Khotan sent as yearly tribute to the imperial court, kept its hold on Chinese scholars even as Qing aristocrats fell for the greens of jadeite. The name comes via Latin from the Spanish piedra de ijada.
Q 29Alexandrite, green by daylight and red under incandescent light, is a rare variety of which mineral?
Chrysoberyl
Chrysoberyl, a beryllium aluminate at 8.5 on the Mohs scale, is a different mineral from beryl despite the name; its other famous variety is cat's eye. Alexandrites over five carats were once thought to come only from Russia's Urals.
Q 30Which Myanmar valley, forced open by the British in 1886, was for centuries the main source of 'pigeon's blood' stones?
Mogok
Mogok lost its crown in the 1990s, when Mong Hsu in central Myanmar began producing and quickly became the world's main mining area for the stone. 'Pigeon blood', the brightest red, still commands a big premium over other grades.