Dem be one of di world rarest jewels – but nobody sabi for sure why pink diamonds dey pink.

Dat one never stop investors to dey seperate dem up for auction and send prices skyrocketing.

For October one new world record dey set for Sotheby sale for Hong Kong when one 8.41-carat pink diamond bin sell for $17,768,041 (£11,438,714) – more dan $2.1m (£1.8m) one carat.

“Everybody dey talk about em, and everybody love dem,” Jeffrey Post tok, curator of di National Gem and Mineral Collection for di Smithsonian National Museum of Natural History for Washington, DC. “Yet you fit tell pipo why dey be pink.”

Oda diamonds get dia colour from chemical impurities wey absorb light. Yellow diamonds contain traces of nitrogen, and blue diamonds contain boron. But dem never find similar impurities for pink diamonds, dis one lead scientists to speculate say di colour fit be di result of some kind of seismic shock wey alter di stone molecular structure.

Di hope now be say cache of brown and pink diamonds from di Argyle mine Western Australia fit solve di mystery. Di mine, wey Rio Tinto own,be di world largest source of pink diamonds, even though dem dey so scarce dat only few dey produced each year.

As well as to reveal wetin make dem pink, scientists hope say to study di diamonds go tell dem more about di history of di planet.

Diamonds be di Earth messengers, Post tok. “Dem come from one hundred miles below di surface and tell us about one part of di Earth wey we no fit visit. Dem also dey give us peek back in time sake of most diamonds form about two to three billion years ago.

“Each one be time capsule, and di pink diamonds, sake of say dem dey different from all di oda diamonds, get different part of di story to tell.”

Scientists don already examine di Argyle diamonds use one mass spectrometer to try to find any trace of impurities wey fit dey cause di pink colour. D machine agitates di diamonds and analyses di chemical structure of di atoms wrey dem release.

“No impurity wey fit dey able to associate so far wit di pink colour inside diamonds,” Post tok. “Spectroscopic measurements no dey show you any additional features wey you fit credit to one particular colouring agent.”

Dem don also use focus on beam to cut tiny trench for di surface of di diamonds and remove one sliver dat fit dey measured under one powerful electron microscope. Dem don discover say most pink diamonds no dey uniformly pink but get pink zones wey dey alternate wit clear areas.

Di zones, dem sabi as twin planes, dey formed by some kind of shock – e possible say di result of volcanic activity wey fling di diamonds to di surface or from something wey happun to dem as dem dey form deep underground.

“Di twin plane self fit no give rise to colour,”Post tok. “But we think say when those twin planes form, and slide back and forth, one against di oda like fault plane, dat kind defect form. Di defect give us di pink colour. But wetin we never dey able to do yet be to find di specific kind of defect.”

Although pink diamonds dey among di most valuable jewels today, 20 years ago dem dey little more dan one geological curiosity. Sales don drive by savvy marketing and growing appreciation of dia uniqueness.

“E really come down to di scarcity,” Richard Revez tok, one gem expert for Florida-based Kravit Estate Department. “When you tok about coloured diamonds, dey already be elite 1% produce in di world. Pink diamonds be di 1% of di 1%.”

E say di most sought-afta diamonds actually be red, but orange, green, blue and yellow dey highly desirable. One orange diamond attract di highest price dem pay per carat for any diamond for auction last year, e sell for $35m, or $2.4m per carat.

“We don crave diamonds for millennia,” Revez tok. Dem probably discover di first gem on river banks for India, but dia existence dey recorded di Greek and Roman history. “E dey believed say e get one vein wey run directly from di heart to di ring finger dat na why we dey wear (diamonds) on our ring fingers. And Cupid arrows dey tipped wit diamonds to pierce di heart easier,” e tok.

Di believe be say Archduke Maximilian of Austria start di tradition of diamond engagement rings among di upper class when e bin present one to Mary of Burgundy for 1477.

But no be until di 1950s wey di international standards to grade diamonds dey set by di Gemological Institute of America (GIA), one classification systemwey dem still dey use today.

But only science fit reveal why pink diamonds be pink.

Pink diamonds fit dey artificially created, di Smithsonian Post tok. And di only way to tell if e be synthetic stone be to understand wetin dey cause di colour to happun naturally.

“Den I fit tell you for sure say dat na diamond wey come out of di earth as oppose to one wey came out of somebody laboratory. It fit make di difference of millions of dollars for value of single diamond, wen we sabi whether e be natural pink or not.”