BY Jenna Hanson |

January 29, 2013

新的研究揭開澳洲神秘的阿蓋爾粉鑽，帶天然呈粉紅色。

來自西部澳洲的阿蓋爾粉鑽，是市面上最有價值的鑽石，但它們天然的粉紅色對科學家仍是個謎。         

然而，對阿蓋爾粉鑽受光變色的新研究，或是鑽石暴露在光線下就會改變顏色的方式，或許可將科學家們在揭開真相時，更往前邁進一步。

在Keal Byrne的帶領下，他是西澳大學博士班學生，使用一套頻率較窄的光來漂白粉鑽的顏色，以了解它們受光變色的行為。

『我們想要更了解這過程，什麼光會移走顏色，甚麼光會把顏色帶回來。所有這些都在了解鑽石的結構。』

『我們希望這更進一步朝向造成粉紅色的真相邁進。』

為什麼鑽石會有顏色

鑽石是從碳原子鏈結在一起，在水晶網格裡，不會吸收光線，造成一顆純鑽石的無色外觀。

有色鑽石像是阿蓋爾粉鑽，以它中心的瑕疵著稱。鑽石網格裡一個或更多的碳原子可能不見，或被不同的元素取代。

這些瑕疵中心夠多，會形成不同的特色。像是吸收光線到一個可見色澤差異的程度。

『不同瑕疵產生不同色澤』

『鑽石裡足夠的足夠氮原子，會讓鑽石顯色為黃鑽；足夠的硼雜質，就會讓鑽石顯色成藍色。』

會讓粉鑽顯色呈粉紅的瑕疵中心是什麼，還不知道。

『這篇論文為市面上最貴重的有色寶石提供新的限制，也就是天然粉紅鑽。』粉紅(到紫色，到紅色)，在天然鑽裏頭，對科學家仍是個謎，而其他的有色鑽石，則都找得到原因可解釋。

艾露薏補充，阿蓋爾粉鑽是拿來做研究的最佳樣品。因為高度飽和的粉紅色中，任何的變化都能輕易被觀察。

基爾則相信粉紅鑽，與其它尚未了解的鑽石瑕疵，對於新生的科技有用。

『對光敏感的鑽石瑕疵，越來越能應用在科學研究的用途。從生化醫學造影，到量子電腦。』

『我們知道越多，就越有可能發現，某些東西有一天可以貢獻在這些科技。』

Uncovering the mystery of pink diamonds

BY Jenna Hanson |

January 29, 2013

New research has shed light on Australia's mysterious Argyle diamonds, which are naturally pink in colour.

ARGYLE DIAMONDS, FROMWestern Australia, are the most valuable diamonds on the market, but their natural pink colour is still a mystery to scientists.

However, new research into the photochromic behaviour of Argyle diamonds – or the way in which the diamonds change colour upon exposure to light – may have brought scientists one step closer to uncovering the truth.

Led by Keal Byrne, a PhD student at the University of Western Australia in Perth, the researchers used a suite of lights with narrow frequencies to bleach the colour from the pink diamonds, in order to understand their photochromic behaviour.

“We are attempting to understand this process better – what light removes the colour, what light brings it back, and what this all means for the diamond's structure,” says Keal.

 “[We] hope that this may be one step towards finally determining what it is that creates the pink colouration in Argyle diamond.”

Why diamonds have colour

Diamonds are made from carbon atoms bonded together in a crystalline lattice that doesn’t absorb light, which results in the colourless appearance characteristic of a pure diamond.

Coloured diamonds, such as Argyle diamonds, have what is known as a defect centre, where one or more of the carbon atoms in the diamond lattice may be missing, or may have been replaced with a different element.

With enough of these defect centres the diamond may take on different properties, such as absorbing light to the point of a visible colour difference.

 “Different defects produce different colours,” says Keal. “Sufficient nitrogen atoms in a diamond will make a diamond appear yellow; enough boron impurities can make a diamond appear blue.”

The defect centres that cause the pink colour in diamonds remain unknown.

Pink diamonds useful in scientific research

The study, which was published recently in the journal Diamond and Related Materials, will contribute significantly to future research, according to Dr Eloise Gaillou from the Natural History Museum of Los Angeles, in California, USA.

 “This paper provides new constraints on the colour centre responsible for the most valuable gems available on the market: natural pink diamonds,” says Eloise.

“The pink (to purple, to red) colour in natural diamonds is still an enigma for scientists, whereas nowadays most other causes of colour in diamonds can be explained.”

Eloise added that Argyle diamonds were the best samples to use for the study, because the highly intense pink colouring means that any changes in colour can be easily observed.

Keal believes that the pink diamonds, and other unexplored diamond defects, may also be useful for emerging technologies.

 “Light-sensitive diamond defects are finding more and more uses in scientific research, from biomedical imaging to quantum computers,” says Keal.

 “The more we learn, the more likely we are to find something that may one day contribute to these technologies.”

http://www.australiangeographic.com.au/news/2013/01/uncovering-the-mystery-of-pink-diamonds