黑钻石

2018-02-22 21:32:32

黑钻石(又称黑金刚石Carbonado)是一种发现在中非共和国及巴西冲积矿床的天然多晶金刚石。它的自然颜色是黑色或暗灰色,比其它钻石有更多更孔隙。

目录

  • 1 不寻常的性质
  • 2 起源
  • 3 参见
  • 4 参考资料
  • 5 外部链接

不寻常的性质

除了另行说明外,黑钻石的特点在这部分是由Heaney et al. (2005)的摘要指出。

黑钻石由于有许多微小的黑色晶体,通常有豌豆大小或更大的聚合多晶体。最独特的是,只有中非共和国及巴西能发现黑钻石,极小部分发现在南非共和国,但却没有在通常发现钻石的庆伯利岩中发现。铅同位素分析晶体约于3亿年前形成,在年轻的沉积岩中。

起源

黑钻石的起源有重大的争议,部分的假计如下:

  1. 有机碳在地球内部的高压下直接转换,如最常见的钻石形成假说。这样黑钻石应该能于全球发现,但仅发现于部分地区。
  2. 冲击变质,如陨石在地球表面冲击引起的。但是,绝大部分冲击引成的六晶体都是六方金刚石,与黑钻石不同。
  3. 自发裂变的铀和钍辐射诱发的形成。但辐射产生的分裂能量太小,不能创造大颗粒晶体的金刚石(500微米)。
  4. Formation inside an earlier-generation giant star in our area, that would have long ago exploded in a supernovae.1
  5. An origin in interstellar space, due to the impact of a supernovae, rather than being thrown from within an exploding star.2

参见

  • 超硬材料

参考资料

  1. ^ Garai, J., Haggerty, S. E., Rekhi, S., and Chance, M., 2006, Astrophysical Journal Letters, vol 653, pp L153-L156 存档副本. 2007-07-30. (原始内容存档于2007-08-09).  Infrared Absorption Investigations Confirm the Extraterrestrial Origin of Carbonado-Diamonds This study suggested that infrared absorption spectra of carbonado are like those of diamonds of extraterrestrial origin; the significant peaks are due to trace abundances of the elements nitrogen and hydrogen.
    The researchers concluded that the mineral formed in an interstellar environment. In this sense, carbonado are theorized to be akin to carbon-rich cosmic dust, likely having formed in an environment near carbon stars. The diamonds were suggested to have been fragments of a body of asteroid size that subsequently fell to Earth as meteorites.
  2. ^ Garai, J., Haggerty, S. E., Rekhi, S., and Chance, M., 2006, Astrophysical Journal Letters, vol 653, pp L153-L156 存档副本. 2007-07-30. (原始内容存档于2007-08-09).  Infrared Absorption Investigations Confirm the Extraterrestrial Origin of Carbonado-Diamonds This study suggested that infrared absorption spectra of carbonado are like those of diamonds of extraterrestrial origin; the significant peaks are due to trace abundances of the elements nitrogen and hydrogen.

外部链接

  • Photo of porous carbonado at National Science Foundation
  • Photo of glossy carbonado and article on possible extraterrestrial origins at PBS Nova
  • Mystery Diamonds: Geoscientists Investigate Rare Carbon Formation ScienceDaily (June 1, 2007) Story
  • Diamonds From Outer Space: Geologists Discover Origin Of Earth's Mysterious Black Diamonds ScienceDaily (January 9, 2007) Story.

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