50 free Crystal trivia questions with answers — science & nature quiz, new questions added Aug 2026.
This crystal trivia quiz covers crystals in every sense of the word: the science (what makes a solid a crystal, the seven crystal systems, quasicrystals, X-ray crystallography and the Nobel Prizes it won), the minerals (quartz and amethyst, halite, bismuth, diamonds, geodes and Herkimer 'diamonds'), the natural wonders (Mexico's Cave of the Crystals, snowflakes and the man who first photographed them) and the crystals people make and sell, from Swarovski and Waterford lead crystal to rock candy and the quartz oscillators inside your watch. It also takes in the folklore and the fakes: crystal balls and John Dee, crystal healing and what the studies found, and the crystal skulls that turned out to be 19th-century German work. Difficulty runs from easy questions anyone with a rock collection can answer to expert ones about crystallography and history. Every answer was checked against a reference page before publishing, so the dates, names and numbers hold up.
30 of 50 questions with answers and explanations. Play the quiz
Q 01The word crystal comes from the Ancient Greek krustallos, which meant both 'rock crystal' and what?
Ice
Greek philosophers including Theophrastus thought quartz was supercooled ice, an idea Pliny the Elder repeated and which lasted into the 17th century.
Q 02Despite the name, lead crystal and crystal glass are actually what kind of solid?
Amorphous solids
Glass has no periodic arrangement of atoms at all, unlike true crystals such as table salt or diamond.
Q 03Crystal structures are grouped into how many crystal systems?
Seven
Halite's cubes belong to the cubic system, while ordinary water ice is hexagonal.
Q 04Which symmetry can quasicrystals show that is impossible for an ordinary periodic crystal?
Five-fold
The holmium-magnesium-zinc quasicrystal can even grow as a pentagonal dodecahedron; the discovery forced crystallographers to redefine the word crystal.
Q 05Quartz defines which value on the Mohs hardness scale?
7
Its name comes from the German Quarz, ultimately from a Slavic word meaning 'hard'; it is a framework of silicon-oxygen tetrahedra with formula SiO2.
Q 06Whose 17th-century study of quartz paved the way for modern crystallography?
Nicolas Steno
Roman naturalist Pliny had believed quartz was permanently frozen ice.
Q 07Amethyst gets its name from a Greek word meaning what?
Not intoxicated
Ancient Greeks carved drinking vessels from it believing it prevented drunkenness; the violet colour comes from irradiated iron impurities.
Q 08The Cave of the Crystals near Naica, Mexico, holds giant crystals of which mineral?
Selenite gypsum
The largest is 11.4 metres long and weighs an estimated 12 tonnes; the chamber reaches 58°C with up to 99% humidity.
Q 09Who discovered the Cave of the Crystals in April 2000?
Two brothers drilling in the mine
Juan and Pedro Sánchez broke into it while drilling; the crystals grew over at least 500,000 years and the cave reflooded by 2015.
Q 10Roughly how long did the Naica crystals take to grow to their enormous size?
At least 500,000 years
Gypsum crystallised extremely slowly once the water cooled below about 56°C above a magma chamber.
Q 11A snowflake's six-fold symmetry comes from what?
The hexagonal crystal structure of ice
Fewer than 0.1% of snowflakes are perfectly symmetrical, and rare twelve-branched flakes still keep the six-fold pattern.
Q 12Guinness lists the largest snowflakes, 15 inches wide, as falling in 1887 at Fort Keogh in which state?
Montana
Normal aggregated flakes top out at 3 or 4 inches.
Q 13Wilson 'Snowflake' Bentley photographed his first snowflake in 1885 on his family farm in which state?
Vermont
He caught flakes on black velvet, attached a bellows camera to a microscope, and popularised the idea that no two snowflakes are alike.
Q 21Under EU rules, glass may only be labelled 'lead crystal' if it contains at least how much lead oxide?
24%
The lead raises the refractive index, giving the sparkle, but it can leach into food and drink; lower-lead glass must be sold as 'crystal glass'.
Q 22Swarovski built its crystal-cutting factory in which Austrian town for hydroelectric power?
Wattens
Founder Daniel Swarovski was born in Bohemia; the company adopted its edelweiss logo in 1899 and now also owns Swarovski Optik and Tyrolit.
Q 23Crystal-making in Waterford, Ireland dates back to 1783 and which pair of founders?
George and William Penrose
Q 14Which physicist won the 1914 Nobel Prize for showing that crystals diffract X-rays?
Max von Laue
The idea came up in a conversation in Munich's English Garden, and the first pattern was shot through a copper sulfate crystal.
Q 15Which father-and-son pair shared the 1915 Nobel Prize in Physics for their crystallography work?
The Braggs
The younger Bragg's law links X-ray scattering to evenly spaced planes of atoms; the first structure solved, in 1914, was table salt.
Q 16What was the first crystal structure solved to atomic resolution, in 1914?
Table salt
Copper, fluorite, calcite and pyrite followed the same year, and spinel in 1915.
Q 17The United Nations proclaimed which year the International Year of Crystallography?
2014
The proclamation came in July 2012, a century after von Laue's diffraction experiment.
Q 18Which French siblings discovered piezoelectricity in 1880 using crystals such as quartz and tourmaline?
The Curies
Pierre and Jacques found quartz and Rochelle salt gave the strongest effect; it now sparks gas lighters and stoves.
Q 19At what frequency does the tuning-fork quartz crystal in nearly all quartz timepieces vibrate?
32,768 Hz
The first quartz clock was built by Warren Marrison at Bell Labs in 1927; Seiko's Caliber 35A of 1969 was the first quartz wristwatch movement.
Q 20Where was the first quartz clock built in 1927?
Bell Labs
Warren Marrison's clock was accurate to 0.01 second per day; Junghans's Astrochron of 1967 was Europe's first consumer quartz clock.
That original glassworks shut in 1851; the modern company's main plant closed in 2009 and the brand now belongs to Fiskars.
Q 24Which 1851 Joseph Paxton building for the Great Exhibition took its nickname from a Punch quip?
The Crystal Palace
Its 293,000 panes of glass were made by Chance Brothers; rebuilt at Sydenham, it burned down in November 1936.
Q 25Rotary jeweller's tool marks on the British Museum's crystal skull date it to which century?
The 19th
The skulls were most likely made in Idar-Oberstein, Germany, from Brazilian quartz, and many passed through Paris dealer Eugène Boban.
Q 26Which German town, famous for working Brazilian quartz, is the likely origin of the "ancient" crystal skulls?
Idar-Oberstein
The British Museum skull came via Tiffany & Co. in New York, and Paris's came from ethnographer Alphonse Pinart.
Q 27Which Elizabethan mathematician and consultant to Queen Elizabeth I is famous for scrying with crystals?
John Dee
The tomb of the fifth-century Frankish king Childeric I even held a small transparent beryl globe.
Q 28What does scientific research say about crystal healing?
Its effects match a placebo
A 1999 study by French and Williams tested real crystals against fakes; the practice is considered pseudoscience.
Q 29Diamond crystallises in which crystal system?
Cubic
Its typical habit is octahedral, and Antoine Lavoisier proved in 1772 that it was pure carbon by burning one under a lens.
Q 30Most natural diamonds are how old?
1 to 3.5 billion years
They reached the surface much later in volcanic eruptions, carried up in kimberlite and lamproite rocks.