98 Fun Facts About Crystal

The word crystal comes from the Ancient Greek krustallos, which meant both 'rock crystal' and what?

Ice: Pliny the Elder was sure rock crystal was a kind of ice, since it turned up only where winter snow froze hardest.

At the atomic level, what kind of material is lead crystal glassware?

Amorphous solids like glass lack a crystal lattice; the name comes from Venetian cristallo, glass made to resemble colourless rock crystal.

Which scientist tied crystals' shapes to their power to twist polarized light, proposing asymmetric molecules?

Louis Pasteur then turned to fermentation, showing that living microbes cause it, work that gave us the word pasteurized.

Which symmetry can quasicrystals show that is impossible for an ordinary periodic crystal?

Five-fold symmetry was thought impossible in crystals, so once quasicrystals showed it, the IUCr rewrote its definition of a crystal in 1992.

Which mineral defines 1, the softest point on the Mohs hardness scale?

Talc is so soft and fine when crushed that it became talcum powder, long used in baby powders.

Whose 1669 study found that quartz crystals keep the same angles between faces whatever their size?

Nicolas Steno soon gave up science for the Catholic Church, becoming a priest and then a bishop.

Amethyst gets its name from a Greek word meaning what?

Not intoxicated: the ancients believed the stone prevented drunkenness, so people wore amethyst while drinking to ward off wine's effects.

The Cave of the Crystals near Naica, Mexico, holds giant crystals of which mineral?

Selenite gypsum beams over 10 metres long grew underwater; once the cave was drained, they risked cracking under their own weight.

Who discovered Mexico's giant Cave of the Crystals at Naica in 2000?

Two brothers drilling in the mine broke into it; in its heat and humidity, researchers could stay only about ten minutes at a time.

Roughly how long did the Naica cave's giant crystals take to grow?

Hundreds of thousands of years: in water barely cooler than 58°C, they grew by about a sheet of paper's thickness every 200 years.

Rubies and sapphires are both crystals of which mineral?

Corundum is so hard and scratch-resistant that lab-grown sapphire covers the windows of supermarket barcode scanners.

Guinness lists the largest snowflakes, 15 inches wide, as falling in 1887 at Fort Keogh in which state?

Montana's record rests on one rancher's unverified claim, and 15 inches lies far outside the normally documented range for snowflakes.

Wilson 'Snowflake' Bentley photographed his first snowflake in 1885 on his family farm in which state?

Vermont farmer Bentley fitted a camera to a microscope and photographed over 5,000 snow crystals without finding two alike.

Which physicist won the 1914 Nobel Prize for showing that crystals diffract X-rays?

Max von Laue's gold Nobel medal was dissolved in acid in Copenhagen in 1940 to hide it from the Nazis; after the war, the gold was recovered and a new medal cast.

Which father-and-son pair shared the 1915 Nobel Prize in Physics for their crystallography work?

The Braggs won while the son, aged 25, was serving in France, locating enemy guns from the sound of their firing.

X-ray studies showed which crystal is built of alternating ions rather than separate molecules?

Table salt's sodium and chlorine atoms sit alternately, ionized rather than paired into molecules, which confirmed ionic bonding as a real type of chemical bond.

Photo 51, a famous 1952 X-ray diffraction image, revealed the shape of which molecule?

DNA's Photo 51, from Rosalind Franklin's X-ray work, was the pattern that let Watson and Crick reveal the double helix.

Which French siblings discovered piezoelectricity in 1880 using crystals such as quartz and tourmaline?

The Curies' effect later became a vital tool when Marie Curie, Pierre's wife, measured faint currents from uranium rays on the way to discovering radium.

What shape is the quartz in most quartz watches?

A tuning fork of quartz typically vibrates 32,768 times a second, a power of 2, so a chain of divide-by-2 circuits yields exactly one tick per second.

Where was the first quartz clock built in 1927?

Bell Labs built its quartz clock while seeking steady frequency standards; by the 1940s, time-standard labs worldwide had switched from pendulums to quartz.

Swarovski built its crystal-cutting factory in which Austrian town for hydroelectric power?

Wattens' hydroelectric power ran the cutting machine Daniel Swarovski had patented, turning crystal cutting into factory work.

Which Irish city's glassworks, founded in 1783, gave its name to one of the world's best-known crystal brands?

Waterford's original glassworks, set up by George and William Penrose, closed in 1851, and the brand was revived only in 1947.

Which magazine's quip gave Joseph Paxton's 1851 Great Exhibition hall the nickname Crystal Palace?

Punch's Douglas Jerrold called Paxton's glass hall 'a palace of very crystal', and the nickname Crystal Palace stuck; the building moved to Sydenham in 1854 and burned down in November 1936.

Which tool left the marks that exposed the British Museum's crystal skull as a fake?

A rotary wheel with abrasive left regular grooves, a technique pre-Columbian carvers, who worked with hand-held tools, almost certainly never used.

Which Elizabethan mathematician and consultant to Queen Elizabeth I is famous for scrying with crystals?

John Dee, Elizabeth I's astrologer and mathematician, used a crystal ball and an obsidian mirror with his medium Edward Kelley to 'converse with angels'; both objects ended up in the British Museum.

What does scientific research say about crystal healing?

Christopher French's experiments with real and fake quartz found the same reported sensations whichever crystals volunteers held, so its effects match a placebo; crystal healing is classed as pseudoscience.

Which mineral is nicknamed fool's gold?

Pyrite struck against metal throws sparks, so some early firearms used it to fire the gun.

Most natural diamonds are how old?

Most natural diamonds, at 1 to 3.5 billion years old, predate the first land plants, so most cannot have come from compressed coal.

The Cullinan, the largest gem-quality rough diamond ever found, came from which present-day country?

Found at South Africa's Premier Mine, the stone was bought by the Transvaal government, given to King Edward VII and cut into nine major stones.

Crunching which sweets in a dark room gives off tiny flashes of blue light?

Wintergreen mints glow because crushed sugar crystals give off mostly ultraviolet light, which the wintergreen oil turns into visible blue.

Halite crystals naturally grow in which shape?

Halite grows as cubes and cleaves perfectly in three directions at right angles, so a broken crystal splits into smaller blocks.

The rainbow colours on lab-grown bismuth 'hopper' crystals come from what?

The colours are thin-film interference in an oxide layer of bismuth whose thickness varies across the surface; the stair-step hopper shape forms because crystal edges grow faster than the faces.

Rock candy is made by letting a supersaturated sugar solution crystallise onto what?

A string or stick, often dusted with sugar first, gives the dissolved sugar seed points to cling to, and the crystals take about a week to grow.

Which Austrian botanist discovered liquid crystals in 1888 when a cholesterol compound seemed to melt twice?

Friedrich Reinitzer turned to physicist Otto Lehmann to explain the double melt, and Lehmann later coined the name liquid crystals.

Large amethyst-lined geodes are a feature of the basalts of which two South American countries?

Brazil and Uruguay's basalt lava flows trapped gas bubbles, leaving cavities that mineral-laden water later lined with amethyst.

What mainly decides whether a snow crystal grows as a plate or a column?

Air temperature sets the form: thin plates near -2°C, slender columns near -6°C, then large thin plates again near -15°C.

Diamond's name derives from a Greek word meaning what?

Diamond comes from Greek adamas, 'unbreakable', yet diamond is brittle, and a well-aimed blow along its cleavage can split it.

Quartz grains change volume abruptly at 573°C, cracking work in which craft?

Pottery firing slows down through the quartz inversion, because the sudden change in the quartz grains' volume can crack, or dunt, the ware.

Which of the British crown jewels holds Cullinan I, the 530-carat Great Star of Africa?

Cullinan I was set in the head of the Sovereign's Sceptre with Cross in 1910 for George V; Cullinan II, the 317-carat Second Star of Africa, sits in the Imperial State Crown.

Gout is caused by needle-shaped crystals that form when the blood holds too much of which substance?

Uric acid crystals build up in and around joints, and if gout goes untreated they can form hard lumps called tophi under the skin.

Which mineral, whose green gem variety is emerald, forms the largest confirmed natural crystal, 18 m long?

Beryl's Madagascar giant weighs about 380 tonnes, yet some reported feldspar crystals may have been even bigger; they were never confirmed as single crystals.

Which impurity turns a diamond crystal slightly blue?

Boron does more than colour the stone: blue diamonds that contain it conduct electricity, while almost all other diamonds are excellent insulators.

Who received the 2011 Nobel Prize in Chemistry for discovering quasicrystals?

Dan Shechtman's finding was so controversial that he was asked to leave his research group, and Linus Pauling was among his fiercest critics.

Tempering gives chocolate its shine and snap by steering which ingredient into one stable crystal form?

Cocoa butter set in the right crystal form also resists bloom, the whitish streaks that appear on chocolate stored too warm.

Which technique pulls large single-crystal boules from a melt, notably silicon for computer chips?

The Czochralski process began by accident, when Jan Czochralski dipped his pen into molten tin instead of his inkwell and drew out a thin metal thread.

What are crystals with obvious, well-formed flat faces called?

Euhedral crystals show sharp, well-developed faces because they grew with free space around them; anhedral grains lack faces, usually because they crystallised jammed against their neighbours.

The angular Widmanstätten patterns seen in iron meteorites result from what?

Extremely slow cooling in space grows the pattern, and acid reveals it because taenite etches more slowly than kamacite.

Which optical property makes a double image appear when you look through a crystal such as calcite?

Birefringence may once have guided ships: some researchers think Viking 'sunstones' were crystals like this, used to find the sun behind cloud.

Which gemstone was branded unlucky after Walter Scott's novel Anne of Geierstein featured an enchanted one?

Opal sales in Europe are said to have halved within a year of the 1829 novel, in which a drop of holy water drains the stone's colour and its wearer soon dies.

Which black volcanic glass, once polished into mirrors, is sharp enough to be tested as a surgical scalpel?

Obsidian forms when lava cools too quickly for crystals to grow, so the 'crystal' on the shop shelf is technically natural glass.

Which golden fossilised tree resin gave electricity its name because it crackles with static when rubbed?

Amber was called elektron by the ancient Greeks, and some of the insects sealed inside it lived alongside the dinosaurs.

Jadarite, a white mineral found in Serbia, nearly matches the formula a 2006 movie gave which fictional substance?

Kryptonite was given a written formula in Superman Returns; the real Serbian mineral lacks the fluorine in that recipe and has no green glow.

Loose calcium crystals called otoconia cause a common form of vertigo when they drift inside which body part?

Inner ear crystals that stray into the balance canals make the room spin, and a doctor can often cure it by tilting the head through a set sequence called the Epley manoeuvre.

The harmless 'wine diamonds' that sometimes grow under a cork are crystals of which baking ingredient?

Cream of tartar is potassium bitartrate, which drops out of chilled wine; the kitchen powder is purified from the same crust left behind in winemakers' vats.

The carat, the unit used to weigh gemstones, takes its name from the seeds of which Mediterranean tree?

Carob seeds served as counterweights because traders believed each weighed the same; they actually vary as much as other seeds, so the modern carat is fixed at 200 milligrams.

Which pale pink stone, made into beads in Mesopotamia by 7000 BC, do crystal healers call the 'love stone'?

Rose quartz was also cut into ownership seals by the Romans, while Egyptians believed the stone could prevent ageing.

Which olive-green August birthstone forms deep in Earth's mantle and has also been collected from meteorites?

Peridot is gem-quality olivine, the same mineral that erodes out of a volcanic cone to turn Hawaii's Papakōlea Beach green.

Which deep-blue Afghan stone was ground into ultramarine, the pigment painters reserved for the Virgin Mary's robes?

Lapis lazuli has been mined in Badakhshan for some six millennia, and it was inlaid in the funeral mask of Tutankhamun.

Nephrite, one of the two minerals sold as jade, is named after which organ it was once believed to heal?

Kidney stone is what the name literally means: the Greek and Latin terms translated the Spanish piedra de ijada, the 'flank stone' worn against pains in the side.

Crystal healers lay stones on seven energy centres of the body known by which Sanskrit word?

Chakras come from Hindu and Buddhist tantric meditation; the familiar set of seven reached the West through a 1919 book, and the rainbow colours and gemstone pairings were added later.

The custom of twelve birthstones is often traced to the gem-set breastplate of which high priest in Exodus?

Aaron wore twelve stones for the Twelve Tribes of Israel, and the first-century historian Josephus tied them to the twelve months of the year.

Carat, colour and cut are three of the 'four Cs' used to grade a diamond; which quality is the fourth?

Clarity measures the tiny inclusions trapped inside a diamond as it formed and the blemishes on its surface, most of them invisible to the naked eye.

Which violet-blue gem, mined only in the hills near Mount Kilimanjaro, was named and launched by Tiffany & Co.?

Tanzanite is dug from a strip about 7 km long near the Mererani Hills; it comes out reddish brown and is heated to bring out the blue.

Which gem, famously mined in Russia's Ural Mountains, looks green in daylight but red by lamplight?

Alexandrite was first mistaken for emerald by the Finnish mineralogist who described it; lamplight carries less green and blue than daylight, so the stone turns red.

Which deep-red January birthstone is thought to be named after the pomegranate, whose seeds its crystals resemble?

Garnet is a whole family of minerals rather than one, and it has served since the Bronze Age both as a gem and, crushed, as an abrasive.

Which banded green mineral names a Winter Palace reception room, where it covers the columns and fireplace?

Malachite's room in Saint Petersburg was the seat of Russia's Provisional Government in 1917; ground to powder, the same mineral served as a green paint pigment from antiquity.

Which New York jeweller gave the Hope Diamond to the Smithsonian in 1958, posting it in a plain brown parcel?

Harry Winston trusted the US Mail: the registered parcel cost $145.29 to send, of which $2.44 was postage and the rest insurance on $1 million.

Which iron mineral, black or silver-grey in the hand, always shows its true colour in a rust-red streak?

Hematite takes its name from the Greek word for blood, and it is the mineral that makes red ochre red.

Which mineral, mined at Castleton in Derbyshire as the purple-blue Blue John, defines 4 on the Mohs hardness scale?

Fluorite often glows under ultraviolet light, and in 1852 George Gabriel Stokes named that effect fluorescence after the mineral.

Which black gem, a fossilised wood found at Whitby, became fashionable as mourning jewellery under Queen Victoria?

Jet gave English the phrase jet-black; it is technically a kind of coal, formed from the wood of trees related to the living Chilean pine.

Which forest-green glass, found mainly in Czechia, was created when a meteorite struck southern Germany?

Moldavite is named after the Moldau, the German name for the Vltava river where the first described pieces were found; the impact also left the Nördlinger Ries crater.

Which golden-brown gemstone owes its silky moving sheen to fibres of crocidolite asbestos altered inside the stone?

Tiger's eye has a blue relative called hawk's eye; the golden-brown colour appears as the fibres turn to the iron mineral limonite.

Tiny crystals of which mineral, found in Western Australia's Jack Hills, are the oldest known material formed on Earth?

Zircon grains from these hills date back to the Hadean, Earth's very first eon, and their chemistry gives geologists a rare window on the infant planet.

The Black Prince's Ruby, set in Britain's Imperial State Crown, is not a ruby at all but which other red gemstone?

Spinel was not chemically told apart from ruby until 1783, by which time this stone was centuries old: Henry V is said to have worn it at Agincourt.

The Koh-i-Noor diamond, worn only by women of Britain's royal family, has a Persian name meaning what?

Mountain of Light is a name first recorded by a Persian biographer of Nader Shah, who seized the diamond from Delhi in 1739; a rumoured curse was later said to fall only on male rulers.

Which pearly gem, loved by Art Nouveau jeweller René Lalique, did Florida adopt as its state gem in 1970?

Moonstone was thought by the Romans to be solidified rays of the Moon; Florida chose it because the lunar missions lifted off from its coast.

Diamond, the hardest natural crystal, and the soft graphite in pencils are both pure forms of which element?

Carbon atoms each grip four neighbours in diamond, but in graphite they form flat sheets that glide past one another, which is why a pencil leaves a mark.

Which 1970s jewellery fad relies on liquid crystals that change colour as the wearer's finger warms or cools?

Mood rings went on sale in 1975 as the Mood Stone; the crystals shift from black through green to deep blue between about 32 and 38 °C.

Which actress's wellness brand Goop paid $145,000 in 2018 to settle a lawsuit over health claims for its stone eggs?

Gwyneth Paltrow's company had sold about 3,000 of the eggs; the settlement also required refunds and barred it from claiming benefits its products do not have.

Which bright yellow element, whose crystals melt into a blood-red liquid when burned, was long known as brimstone?

Sulfur's old name means 'burning stone', and it burns with a blue flame; volcanic deposits of it give Jupiter's moon Io its yellow and orange colours.

Which country, home to the famous Muzo and Chivor mines, has historically produced more emeralds than any other?

Colombia's deposits were so rich that emerald mining in ancient Egypt, under way since 1500 BC, ceased after they were discovered.

Which pale blue March birthstone did sailors carry as a lucky charm in the belief that it calmed the waves?

Aquamarine was said in old tales to come from the treasure chests of mermaids, and its sea-blue colour is caused by traces of iron.

At Crater of Diamonds State Park, visitors may keep any gemstone they dig from a ploughed field in which US state?

Arkansas's field has yielded diamonds since 1906, among them the Uncle Sam, at over 40 carats the largest diamond ever found in the United States.

Which naturally magnetised stone, a form of the mineral magnetite, was suspended to make the first compasses?

Lodestone means 'leading stone' in Middle English, a nod to navigation; only a small share of the world's magnetite is found magnetised this way.

Sunstone and amazonite both belong to which mineral group, which makes up more than half of Earth's crust?

Feldspar is in the kitchen cupboard as well as the ground: it is a standard raw material for glass and ceramics, from bottles to tableware and tiles.

Early crystal radio sets picked up broadcasts using a fine wire touching a crystal of which lead ore?

Galena touched by a fine wire, the 'cat's whisker', was the first kind of semiconductor diode; a working spot on the crystal had to be found by trial and error before each use.

Most of which golden-yellow gem sold in shops is really purple amethyst that has been heated until its colour changes?

Citrine takes its name from the citron, a lemon-like fruit; the natural stone is rare, so amethyst baked to a few hundred degrees supplies most of the market.

Clear rock crystal is built from atoms of just two elements, silicon and which other?

Oxygen atoms are shared between neighbouring silicon atoms, tying the whole crystal into one continuous framework with the formula SiO2.

When a jar of honey turns cloudy and grainy, which of its sugars is coming out of solution as crystals?

Glucose settles out as solid grains while the fructose stays liquid, which is why tupelo honey, low in the former, hardly ever sets.

Which 563-carat sapphire was stolen from New York's American Museum of Natural History in a 1964 heist?

Star of India was the only gem in the hall protected by an alarm, and its battery was dead; the stone turned up months later in a Miami bus locker.

Larimar, a sea-blue stone named by its finder after his daughter Larissa, is found only in which Caribbean country?

Dominican Republic miners dig it near Barahona; Miguel Méndez joined Larissa to mar, Spanish for sea, when he rediscovered the stone on a beach in 1974.

Goldstone, the glittering 'gem' invented by Venetian glassmakers, gets its sparkle from tiny crystals of which metal?

Copper crystals form inside the molten glass only when the furnace is starved of air; the Miotti family of Venice devised the recipe in the seventeenth century under licence from the Doge.

Which scarlet mineral, the source of the pigment vermilion, is handled with care because it is the main ore of mercury?

Cinnabar is poisonous because of the mercury locked inside it, a danger recognised as early as ancient Rome.

Tooth enamel, the hardest substance in the human body, is about 96% mineral, mostly crystals of what?

Hydroxyapatite is a crystalline calcium phosphate that makes enamel strong but brittle, and once it has worn away the body cannot grow it back.

Which island nation, one of the main producers of healing crystals, mines many of them in unsafe pits dug by hand?

Madagascar's pits are often worked by parents and children together with shovels, for around 20 cents per kilogram of stone.

Which Nobel-winning physicist proposed 'time crystals', matter whose pattern repeats in time, in 2012?

Frank Wilczek put forward the idea with Alfred Shapere; such a crystal breaks no law of thermodynamics, because it cannot be tapped as a perpetual store of work.

Diamond was confirmed as the birthstone for which month when American jewellers standardised the list in 1912?

April's stone was fixed at a Kansas City meeting of the National Association of Jewelers; older lists had offered sapphire as an alternative for the month.

The Mogok Valley, for centuries the world's main source of fine rubies, lies in which Southeast Asian country?

Myanmar's Mogok stones are famed for the deepest red, known in the trade as pigeon blood, a shade that commands a large premium over other rubies.