2007-12-04 03:08:21 · 4 answers · asked by Yogi 2 in Science & Mathematics ➔ Earth Sciences & Geology
Early theories on origin
The origin of carbonado is controversial, with several hypotheses proposed:
1. Direct conversion of organic carbon under high-pressure conditions (the Earth's interior.) This is the standard, geological process of diamond formation. The problem with this hypothesis is that, were carbonado formed by phase transformation of organic graphite inside the Earth, they would be found all over the world. However, carbonado appears only in the Central African Republic and Brazil, in areas that are far from other diamond deposits.
2. Shock metamorphism induced by meteoritic impact at the Earth's surface. According to this hypothesis, carbonado were created by meteoric impact. The problem with this hypothesis is that shock-induced natural polycrystalline diamonds usually have hexagonal diamond (lonsdaleite) inside the samples, and carbonado does not.
3. Radiation-induced diamond formation by spontaneous fission of uranium and thorium. The problem with this hypothesis is that the energy of radiogenic fission is too small to create polycrystalline diamonds of the large grain size of carbonado (up to 500 micrometers).
[edit] Extraterrestrial origin
A team of U.S. geologists have published evidence relating to a different origin of these black diamonds: interstellar space. They have found that black diamonds contain trace elements of nitrogen and hydrogen which they claim are sure indicators of an extraterrestrial origin.
The study published in 2006 by Stephen Haggerty and Jozsef Garai, of Florida International University, analyzed the hydrogen in black diamond samples using infrared-detection instruments at the Brookhaven National Laboratory. The researchers found that the chemical properties of carbonado indicated that the mineral formed in a supernova explosion that took place prior to the formation of our Solar System.
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 eventually incorporated into solid bodies that subsequently fell to Earth as meteorites.[1]
[edit] External links
* Photo of porous carbonado at National Science Foundation
* Photo of glossy carbonado and article on possible extraterrestrial origins at PBS Nova
[edit] See also
* Material properties of diamond
* Amsterdam Diamond
2007-12-04 04:23:36 · answer #1 · answered by Loren S 7 · 0⤊ 0⤋
If indeed “a diamond is forever,” the most primitive origins of Earth’s so-called black diamonds were in deep, universal time, geologists have found—they came from space.
A polished and cut black diamond (inset), along with a roughly 12 mm wide unprocessed one. (Courtesy NSF)
The study of the rare black gems, also called carbonado diamonds, comes from a research group including Jozsef Garai and Stephen Haggerty of Florida International University.
2007-12-04 03:19:37 · answer #2 · answered by shri 2 · 0⤊ 0⤋
Ski resorts!
2007-12-04 03:11:49 · answer #3 · answered by Trader G 6 · 0⤊ 0⤋
they come from your butt when u got diarrhea
2007-12-04 12:10:12 · answer #4 · answered by adam 2 · 0⤊ 0⤋