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60 free Ruby trivia questions with answers — nature quiz, new questions added Aug 2026.
This ruby trivia quiz covers the red variety of corundum that has been prized for at least two thousand years and today includes both the most expensive coloured gemstone ever sold and the crystal at the heart of the first laser. The easy questions cover the colour, the birthstone month, the hardness and the mineral it shares with sapphire. From there the quiz moves into the science: the chromium that makes it red, the fluorescence that makes it glow, the rutile 'silk' inside every natural stone, star rubies, heat treatment and lead-glass filling. The hard end covers the Mogok Valley and Mong Hsu, Mozambique's Montepuez mine, the only rubies in mainland Europe, three-billion-year-old Greenland stones, the Verneuil process, Theodore Maiman's 1960 laser, the Black Prince's Ruby that is really a spinel, the Sunrise Ruby and the Estrela de Fura, Elizabeth Taylor's ring, the Rosser Reeves star ruby and the $32.5 million pair of slippers. Every answer was checked against encyclopaedia entries on ruby, the named stones, the ruby laser and the ruby slippers before publishing, and the supporting sentence is stored with each question. Our emerald and gemstone quizzes are natural next stops.
30 of 60 questions with answers and explanations. Play the quiz
Q 01Ruby is a red variety of which mineral?
Corundum
Every other gem-quality colour of the same mineral is called sapphire, so rubies are sometimes dubbed red sapphires.
Q 02Which element gives a ruby its red colour?
Chromium
About one percent of the aluminium ions replaced by it is enough to turn the crystal red.
Q 03Ruby is the traditional birthstone for which month?
July
Garnet, January's stone, is usually a deeper, less pink red.
Q 04What is the hardness of ruby on the Mohs scale?
9
Among natural gems only diamond and moissanite are harder.
Q 05The word ruby comes from the Latin 'ruber', meaning what?
Red
It is one of the traditional cardinal gems with amethyst, sapphire, emerald and diamond.
Q 06What name is given to the brightest, most valuable shade of ruby red?
Pigeon blood
Stones of that colour command a large premium over rubies of otherwise similar quality.
Q 07What is the chemical make-up of ruby?
Aluminium oxide
The pure mineral is colourless; only impurities give it colour.
Q 08What are the needle-like rutile inclusions found in all natural rubies called?
Silk
Gemologists use them to tell natural stones from synthetics; a ruby with none may have been treated.
Q 09What optical effect do 'star rubies' display?
Asterism
Light reflecting off the oriented needle inclusions produces a three- or six-pointed star, so these stones are cut as cabochons.
Q 10At what wavelength does ruby fluoresce, adding to its red glow?
694 nanometres
That same emission is what a ruby laser amplifies into coherent red light.
Q 11In the United States, a red-family gem that falls below a minimum colour saturation is sold as what?
Pink sapphire
The distinction only arose in the 20th century and is still debated.
Q 12Which valley in Upper Myanmar was for centuries the world's main source of rubies?
Mogok
Mong Hsu took over as the main mining area in the 1990s.
Q 13Which African country became the top source of gem-quality rubies after a 2009 discovery?
Mozambique
Its Montepuez mine reportedly produced about 10 million carats in 2022.
Q 14Which is the only country in mainland Europe with naturally occurring rubies?
Q 21How much does the Black Prince's Ruby weigh?
170 carats
It is about 4.3 cm long and probably came from Badakhshan in modern Afghanistan.
Q 22What is the Sunrise Ruby named after?
A poem by Rumi
The 25.59-carat pigeon-blood stone was mounted by Cartier between two heptagonal diamonds.
Q 23For how much did the Sunrise Ruby sell at auction in Switzerland in May 2015?
US$30 million
At the time it was the most expensive coloured gemstone ever sold.
Which ruby holds the record as the most valuable ever sold at auction?
North Macedonia
Found near Prilep, they have a distinctive raspberry colour.
Q 15Rubies from which territory are said to be among the oldest in the world, at about 3 billion years?
Greenland
The Aappaluttoq mine south of Nuuk opened in 2017 but was later suspended for poor production.
Q 16What is the most common treatment applied to rubies?
Heat
Temperatures around 1,800 C remove purple tinge and needle inclusions; untreated stones command a large premium.
Q 17What material is used to fill fractures in low-grade rubies to make them fit for jewellery?
Lead glass
The process involves cleaning with hydrogen fluoride and two rounds of heating.
Q 18Which red gemstone is often found alongside rubies and was long mistaken for them?
Spinel
The finest red examples now fetch prices approaching all but the best rubies.
Q 19The Black Prince's Ruby in the Imperial State Crown is actually what?
A spinel
Such stones were once called 'balas rubies'; the impostor mineral was only chemically distinguished from ruby in the 18th century.
Q 20Which English king is said to have worn the Black Prince's Ruby at Agincourt in 1415?
Henry V
Legend says the Spanish king Peter of Castile gave the stone to the Black Prince in 1367.
Estrela de Fura
Its name means Star of Fura, after the mining company that found it in southern Africa.
Q 25What happened to the Liberty Bell Ruby, the largest mined ruby in the world, in 2011?
It was stolen in a heist
The sculpted stone has never been recovered.
Q 26Whose 8.24-carat ruby ring broke the price-per-carat record in 2011?
Elizabeth Taylor
Christie's sold her whole jewellery collection that December, including a ruby necklace that also fetched millions.
Q 27The 138.7-carat Rosser Reeves Ruby is famous for what feature?
A well-defined star
The advertising mogul who donated it to the Smithsonian in 1965 carried it as a lucky charm and called it 'his baby'.
Q 28In which country was the Rosser Reeves Ruby mined?
Sri Lanka
Reeves liked to claim he bought it at auction in Istanbul; he actually acquired it through New York dealers.
Q 29The 23.1-carat Carmen Lucia Ruby at the Smithsonian was mined in which region in the 1930s?
Mogok, Burma
Businessman Peter Buck donated it in memory of his late wife.
Q 30Who built the world's first working laser, using a synthetic ruby, in 1960?
Theodore Maiman
He fired it up at Hughes Research Laboratories on 16 May 1960, and the prototype still works.