50 Fun Facts About Pearls

Inside which part of a mollusc does a pearl form?

The mantle is the soft tissue that also secretes the shell, and it coats any intruder in layer after layer of nacre.

Pearls are made mainly of which mineral?

It is deposited as aragonite, or a mix of aragonite and calcite, in concentric layers, just like the shell itself.

What is the name for the substance, also called mother-of-pearl, that pearls are built from?

It is a combination of aragonite platelets and the horn-like protein conchiolin.

Why does nacre appear iridescent?

The layers reflect, refract and diffract light; the thinner and more numerous they are, the finer the lustre.

The popular belief that pearls start around a grain of sand is described as what?

Parasites, organic debris or displaced mantle tissue are the usual triggers.

Which common household liquid can dissolve a pearl?

The acetic acid reacts with the calcium carbonate to give calcium acetate and carbon dioxide, which is how Cleopatra's famous wager supposedly worked.

Per Pliny the Elder, which queen dissolved a priceless pearl in a drink to win a dinner-party bet?

Pliny valued the pearl at tens of millions of sesterces.

What word describes pearls that are irregular rather than round?

Perfectly round, smooth pearls command the highest prices, but baroque shapes have their own market.

Which examination technique is used to tell a natural pearl from a beaded cultured pearl?

A beaded cultured pearl shows a different internal structure; natural pearls show growth rings separated by thin layers of conchiolin.

Rubbing two real pearls together feels slightly gritty because of what?

Imitation pearls are completely smooth, which is why the tooth test works.

Glass imitation pearls are traditionally coated with 'essence d'Orient', a solution made from what?

Other fakes are simply cut from mother-of-pearl, coral or conch shell.

The English word 'pearl' ultimately comes from the Latin 'perna', meaning what?

The name compares the pearl-bearing bivalve to a ham or leg of mutton.

The Old Persian word for pearl, margarita, is the origin of which girl's name?

It also gives the pearl-mussel family its scientific name, Margaritiferidae.

Which Japanese entrepreneur is credited with creating the first cultured pearl, in 1893?

After near-bankruptcy he produced hemispherical pearls on 11 July 1893 at Ago Bay; his company still bears his name.

What business did the father of the cultured-pearl pioneer run in Toba?

Young Kokichi was hooked on pearls by watching the divers of Ise unload their catch.

Which inventor met Mikimoto in 1927 and marvelled at his cultured pearls?

Mikimoto's patented work is also behind the Phoenix crown worn by Miss Universe.

Which British biologist working in Australia first developed the accepted pearl-culturing process?

He passed the method to Tatsuhei Mise and Tokichi Nishikawa; Nishikawa patented it in 1916 and married Mikimoto's daughter.

In which year was the pearl-culturing patent granted in Japan?

By the 1950s women across the developed world could afford a cultured strand, and natural pearls became a tiny niche.

Akoya pearls come from Pinctada fucata, a small oyster native to the coasts of which two countries?

Because the oyster is only 6 to 8 cm across, akoya pearls over 10 mm are extremely rare.

Which oyster produces the true South Sea pearl, the largest and most valuable of cultured pearls?

It has gold-lipped and silver-lipped varieties, and the Philippines made the South Sea pearl its national gem in 1996.

Tahitian 'black' pearls are grown in which species of oyster?

The black-lip oyster is also farmed in the Cook Islands and Fiji; a truly black pearl is extremely rare.

Why can Tahitian pearls never be mass-produced like freshwater pearls?

Freshwater mussels, by contrast, can carry multiple implants at once.

Most freshwater cultured pearls sold in the 21st century come from which country?

Japan pioneered whole freshwater pearls in Lake Biwa, but that industry has nearly vanished.

What is a 'keshi'?

It forms when the mantle graft slips off the bead; today many keshi are produced on purpose.

21st-century natural pearling is confined mostly to the seas off which country?

Bahrain's Pearling Path, with three oyster beds and 17 buildings on Muharraq, became a World Heritage Site in 2012.

Pliny the Elder praised the pearl fishery of which body of water as the most productive in the world?

Sri Lanka's Gulf of Mannar was another ancient centre, mentioned in the chronicle Mahavamsa.

Spanish conquistadors found a vast pearl bed around Cubagua and Margarita, islands off which country?

A 1558 royal decree ordered that only African slaves, not natives, be used for the deadly diving work.

Pearls were said to be one of the attractions that drew which Roman leader to Britain?

Freshwater pearl mussels still live in Scottish rivers, where they are now legally protected.

Who bought La Peregrina, the pearl once owned by Spanish kings, at Sotheby's in 1969?

He paid 37,000 dollars and gave it to Elizabeth Taylor as a Valentine's Day gift.

Where did Elizabeth Taylor find La Peregrina after it went missing in her Caesars Palace suite?

She casually opened the dog's mouth and there was 'the most perfect pearl in the world'.

La Peregrina passed from Napoleon III to which British aristocratic family, who kept it until 1969?

The exiled emperor sold it to James Hamilton, Marquess and later Duke of Abercorn, for his wife Louisa.

The Pearl of Lao Tzu, also called the Pearl of Allah, is a non-nacreous pearl from which animal?

Found off Palawan in the Philippines, it is 24 cm across and weighs 6.4 kg.

The largest known pearl, the Pearl of Puerto, weighs roughly how much?

A fisherman from Puerto Princesa on Palawan found the 67 cm giant-clam pearl; it weighs 34 kg.

Rare pink 'flame structure' pearls of the Caribbean come from which animal?

They are non-nacreous, and the best show a shimmering 'flame structure' on the surface.

Blue-toned abalone 'blister' pearls are unique to the waters of which country?

Their vivid colours are often compared to opal.

Girl with a Pearl Earring, painted around 1665, is the work of which Dutch master?

It is a tronie, a study of a head not meant as a portrait, and hangs in the Mauritshuis in The Hague.

In 2014 a Dutch astrophysicist argued the famous painted earring looks more like what than pearl?

Vincent Icke cited its specular reflection, pear shape and sheer size.

Which author wrote The Pearl, a novella about a poor diver named Kino in La Paz, Baja California?

It began as a short story in 1945 and grew from a Mexican folk tale he heard on a 1940 visit.

Japan's traditional 'ama' divers, famous for gathering pearls and abalone, are mostly what?

Records of the sea women go back to AD 927; they traditionally wear white, partly to ward off sharks.

Broome, whose pearling industry began in the 1880s, is a town in which Australian state or territory?

It lies in the Kimberley region, over 2,000 km north of Perth, and drew Japanese, Malay and Chinese divers.

Which Philippine president declared the South Sea pearl the national gem in 1996?

Golden South Sea pearls are especially associated with the Philippines and Indonesia.

In the Book of Revelation, the twelve gates of the New Jerusalem are each made from what?

This is the origin of the phrase 'pearly gates'.

Pearls from the rainbow-lipped Pteria sterna oyster do what under ultraviolet light?

The Mexican farm markets them as Concha Nacar.

What is the horn-like organic compound that binds the aragonite crystals in nacre?

Aragonite plus this binder is what makes up mother-of-pearl.

In which year was pearling banned in the UK to protect endangered river mussels?

Publicity over the Abernethy pearl from the River Tay had drawn 'weekend warriors' who stripped mussel beds in the 1970s and 80s.

Japanese freshwater pearl farming began in 1914 using mussels native to which lake?

Japan's largest and oldest lake sits near Kyoto, and its name became shorthand for fine freshwater pearls.

Roughly how many metric tons of freshwater pearls does China produce per year?

Japanese units such as the kan and momme are still encountered in the pearl trade.

Which Japanese weight unit is still the standard for loose pearls and strands among dealers?

The Japanese have used the measure for centuries.

Which Hindu text first documented the sacred Nine Pearls?

Ayurveda also prescribes pearl powder as a digestive stimulant and a treatment for mental ailments.

Which Scottish Highland river was noted for the finest rose-pink freshwater pearls?

Scottish Travellers did most of the pearling, and two firms are still licensed to sell pre-1998 pearls.