58 Fun Facts About Ruby

Ruby is a red variety of which mineral?

Corundum is so hard that emery, a dark grit rich in it, is glued to nail files and sandpaper to grind down almost anything softer.

Which element gives a ruby its red colour?

Chromium is a two-faced colourist: a trace of it turns this gem red, yet the very same element is what paints emeralds green.

Ruby is the traditional birthstone for which month?

July has been ruby's month officially since 1912, when America's jewellers met and agreed a single modern birthstone list to tidy up centuries of competing traditions.

Ruby scores 9 and diamond 10 on which hardness scale?

Mohs hardness is only a pecking order of what scratches what, drawn up by Friedrich Mohs in 1812, so its steps are uneven: diamond at 10 is about four times as hard as ruby at 9.

The word ruby traces back to a word for 'red' in which ancient language?

Latin: medieval writers called the gem rubinus lapis, 'red stone', and the same red root gives us rubric, a heading that scribes once wrote in red ink.

What name is given to the brightest, most valuable shade of ruby red?

Pigeon blood need not be a pure red: gem bodies allow the prized shade a slight purplish tint, and a stone that earns the name commands premium prices.

What is the chemical make-up of ruby?

Aluminium oxide is colourless when pure, so a ruby owes all its colour to a trace impurity; the same compound forms the thin skin that stops aluminium foil and cans from corroding.

Which fabric lends its name to the fine, needle-like rutile inclusions found inside many natural rubies?

Silk sounds like a flaw, yet these fine needles can scatter light into facets that would otherwise look dark, so a little of it can make a ruby more beautiful, not less.

What optical effect do 'star rubies' display?

Asterism comes from the Greek for star: light bouncing off aligned needle inclusions draws the rays, which only show if the cutter leaves a smooth dome instead of facets.

Which effect makes the finest rubies seem to glow from within in daylight?

Fluorescence is triggered even by the ultraviolet in ordinary daylight, and the red light the gem gives off in response deepens its own colour.

In the United States, a stone too pale to meet the minimum colour saturation for ruby is sold as what?

Pink sapphire is a label barely a century old and still argued over: some gem-producing countries have always counted pink stones as rubies, while the markets that buy them split the two apart.

Which country's Mogok valley was for centuries the world's main source of rubies?

Myanmar, the former Burma, is where warriors are said to have pushed rubies under their skin in the belief that this made them invincible in battle.

Rubies found near Montepuez in 2009 turned which African country into a major new source of the gem?

Mozambique had no known rubies near Montepuez until 2009, yet within a decade its mines ranked among the most prolific on Earth and their best stones were being compared with Asia's finest.

Ancient Sanskrit gave ruby a name that translates as what?

King of precious stones: the name is ratnaraj, whose 'raj' is the royal word heard in maharaja, and ancient Hindus held that offering fine rubies to Krishna would see them reborn as emperors.

In 2017, a ruby mine opened near Aappaluttoq on which northern island?

Greenland's mine kept every ruby in one company's hands from the rock face to the finished gem, a mine-to-market paper trail that is almost unheard of for coloured stones.

What is the most common treatment applied to rubies?

Heat is so routine that buyers assume almost every ruby has been cooked to deepen its colour and clear its haze, so a fine stone proven untouched is the rare exception and commands a large premium.

What material is used to fill fractures in low-grade rubies to make them fit for jewellery?

Lead glass seeps into the cracks and makes a cloudy stone look clear, but the trade values such rubies far below other stones, and the delicate filler needs gentle cleaning.

Traditional ruby-red 'cranberry' glass gets its colour from tiny particles of which precious metal?

Gold gives the glass its glowing red, a recipe lost for centuries and rediscovered by 17th-century alchemists, and the precious ingredient is why it has always been a luxury.

The Black Prince's Ruby, a famous stone in Britain's Crown Jewels, is actually what?

A spinel: for centuries any big red gem was simply called a ruby, and only in the 18th century did chemists show that stones like this one were a different mineral altogether.

Which English king is said to have worn the Black Prince's Ruby at Agincourt in 1415?

Henry V is said to have worn it set in his helmet at Agincourt, though the Royal Collection admits nobody can prove today's jewel is that same stone.

Which crown holds the Black Prince's Ruby?

The Imperial State Crown is the working crown: the monarch is crowned with St Edward's Crown, then swaps it for this one to leave the Abbey, the great red stone mounted just above the Cullinan II diamond.

What is the Sunrise Ruby named after?

A poem by Rumi gave the gem its name: the 13th-century Persian mystic has sold millions of books in modern translation and is often described as the best-selling poet in the United States.

For how much did the Sunrise Ruby sell at auction in Switzerland in May 2015?

US$30 million made it the costliest coloured gemstone ever auctioned at the time, yet when the same ring came back to auction in Geneva in 2023 it fetched less than half that.

Estrela de Fura, a record-setting ruby, takes its name from the official language of its African homeland, which is what?

Portuguese for 'Star of Fura', after the firm that unearthed it in 2022: cutters ground away almost half of the 101-carat rough, and the finished gem sold for $34.8 million in 2023.

What happened to the giant carved Liberty Bell Ruby in 2011?

It was stolen in a heist: armed robbers tied up the staff of a Delaware jewellery store and smashed the cases with hammers, and none of the haul had been recovered when the gang was charged in 2014.

Whose 8.24-carat ruby ring broke the price-per-carat record in 2011?

Christie's sold her whole jewellery collection that December, including a ruby necklace that also fetched millions.

In the King James Bible's Book of Proverbs, whose price is said to be 'far above rubies'?

A virtuous woman: the verse opens a 22-line acrostic in which each line starts with the next letter of the Hebrew alphabet, and many Jewish families sing it at the Friday-night Sabbath table.

Which comedian played the flamboyant media star Ruby Rhod in the 1997 film The Fifth Element?

Chris Tucker inherited the part from a pop star: Prince was first lined up to play Ruby Rhod, and Jean Paul Gaultier's costume sketches for him were later shown in a museum.

Dallas nightclub owner Jack Ruby is remembered for shooting which man in front of live television cameras?

Lee Harvey Oswald was being led through the basement of Dallas police headquarters for transfer to the county jail, two days after President Kennedy's assassination, when Ruby shot him.

In 1960, Theodore Maiman used a synthetic ruby rod to build the world's first working example of which device?

The laser: rivals had dismissed ruby as a material that would never work, but Maiman found errors in their sums, and his small rod fired the first beam on 16 May 1960.

Which band topped the US chart in 1967 with the ballad 'Ruby Tuesday'?

The Rolling Stones meant it as a B-side, but many American radio stations shied away from the risqué 'Let's Spend the Night Together' and played the flip instead.

In which country did chemist Auguste Verneuil devise the flame-fusion process still used to make synthetic rubies?

France: working in Paris, Verneuil dripped a fine powder through a fierce flame so that it rebuilt itself as a single crystal, and his furnace design has barely changed in over a century.

The red throat patch that gives the ruby-throated hummingbird its name is worn by which birds?

Only adult males wear the red throat, and it is iridescent, a trick of the light: in most lights the famous patch simply looks black.

What tell-tale flaws can magnification reveal in a flame-fusion synthetic ruby?

Curved striae and gas bubbles betray a stone grown in a flame, because natural crystals build up in straight lines; a ruby with no flaws at all is itself a warning sign.

A mechanical watch marked '17 jewels' uses tiny synthetic rubies to do which job?

Act as low-friction bearings: the steel pivots of the wheels turn in holes drilled through the hard, polished stones, which barely wear, so the watch stays accurate for decades.

In traditional Hindu astrology, ruby is the gemstone of which heavenly body?

The Sun: in a nine-gem navaratna jewel the ruby is set at the very centre as the stone of the sun god Surya, with a gem for the Moon and each planet arranged around it.

Legend held that a ruby dropped into water could do what to it?

Bring it to a boil: the gem's red glow was taken for an unquenchable flame, one said to shine straight through any clothing or wrapping that tried to hide it.

In L. Frank Baum's original novel, what were Dorothy's magic shoes made of before the film made them ruby?

Silver: in the book the shoes do not even make it home, slipping off during Dorothy's flight back to Kansas and ending up lost forever in the desert.

How much did the once-stolen pair of ruby slippers fetch at auction in December 2024, fees included?

$32.5 million was about eleven times the estimate; in 2012 donors including Leonardo DiCaprio and Steven Spielberg had bought another pair for the Academy's film museum.

Marvel's ruby-red Godstone first turned astronaut John Jameson into a werewolf in the pages of which hero's comic?

Spider-Man: John is the astronaut son of the hero's newspaper nemesis, J. Jonah Jameson; he found the gem on the Moon and wore it as a pendant, until it fused to his neck and moonlight made him Man-Wolf.

For centuries, rubies, garnets and other red gems all went by which name, now more familiar as a painful skin abscess?

Carbuncle started out meaning 'little coal': the gems were thought to glow like embers, and the name later passed to red, inflamed swellings on the skin.

Jewel thief Murf the Surf stole the DeLong Star Ruby in 1964 from a museum in which city?

New York's American Museum of Natural History got the ruby back only when John D. MacArthur, the millionaire behind the 'genius grants', paid a $25,000 ransom and collected it from a Florida phone booth.

Rubies are rare in the United States, but they do turn up in the Cowee Valley of which state?

North Carolina: the valley's mines are open to the public, and thousands of visitors a year pay to wash buckets of gravel there in the hope of taking home a ruby of their own.

Ruby and tawny are the two main red styles of which fortified wine?

Port: ruby is bottled young from sealed tanks so that it keeps its bright red, while tawny spends years in wooden casks, where slow contact with the air fades it to the brown of its name.

Apart from diamond itself, which gem, popular as a diamond alternative, is harder than ruby?

Moissanite mimics diamond so closely that the thermal testers jewellers long relied on to catch fakes can read it as the real thing.

Ruby Falls, an underground waterfall named for its discoverer's wife, lies inside Lookout Mountain in which US state?

Tennessee: crews drilling a lift shaft towards a different cave in 1928 broke into an unknown passage, and Leo Lambert followed it to the waterfall he then named after his wife, Ruby.

Ruby chocolate, naturally pink and unveiled in 2017, first went on sale in Japan and South Korea coating which bar?

KitKat: the pink bar tastes faintly of berries, yet its makers insist that no colouring or fruit flavouring goes in, and that both the colour and the tang come from the cocoa bean itself.

Pokémon Ruby, released with a twin version in 2002, was the first main Pokémon game on which Nintendo handheld?

Game Boy Advance: Ruby was the first Pokémon game to send two Pokémon into battle at once, and these double battles have been part of the series ever since.

Which singer and his band The First Edition had a 1969 hit with 'Ruby, Don't Take Your Love to Town'?

Kenny Rogers sang it while the Vietnam War raged, so listeners took its paralysed narrator for a Vietnam veteran, but writer Mel Tillis had based him on a man wounded in the Second World War.

The Smithsonian's Carmen Lúcia Ruby was donated in his late wife's memory by Peter Buck, co-founder of which sandwich chain?

Subway began as a sideline: Buck, a nuclear physicist by training, put up the money for a friend's single sandwich shop, which grew into the chain and, decades later, paid for the ruby.

Why were Dorothy's shoes changed to ruby for the 1939 film The Wizard of Oz?

To show off three-strip Technicolor is the accepted reason, red standing out against the yellow brick road; on set the sequins were really burgundy, because true red would have filmed as orange.

Who created the Ruby programming language, conceived in 1993 in Japan?

Yukihiro Matsumoto, 'Matz' to his users, says the language exists to make programmers happy: he wanted them to enjoy the creative side of coding instead of fighting their tools.

Ruby's creator chose a gemstone name for his programming language as a playful nod to which older language?

Perl: the gem name began as a joke on it, and only later did Ruby's creator notice that pearl and ruby are the birthstones of back-to-back months, a fitting order for the newer language.

Which web framework is credited with a surge of interest in the Ruby language around 2005?

Rails was not planned as a product: David Heinemeier Hansson wrote it while building the project tool Basecamp, then released the code for anyone to use in 2004.

Ruby Bridges desegregated which New Orleans elementary school on November 14, 1960?

William Frantz emptied as white parents pulled their children out, so Bridges spent the year as the only pupil of Barbara Henry, a teacher from Boston.

Which Norman Rockwell painting, published in Look in 1964, depicts Ruby Bridges walking to school?

The Problem We All Live With hung outside the Oval Office in 2011, where President Obama stood before it with Bridges and told her that without people like her he might not be there.

Which child psychiatrist counselled Ruby Bridges weekly and later wrote The Story of Ruby Bridges?

Robert Coles was never assigned to her: he volunteered after seeing her walk through the mob, and went on to study how desegregation affected children.

Which Indianapolis institution re-creates Ruby Bridges's classroom beside Anne Frank's annex and Ryan White's bedroom?

The Children's Museum stages live theatre inside the rooms: visitors sit in the replica classroom while an actor performs her story.