Friday, June 5, 2009

Diamonds

Everyone knows about diamond. It's the shiny, clear stuff that you pay way too much for to put on rings. It's also one of the best naturally occuring thermal conductors, the hardest natural material known, and are made in volcanoes, meteorite impacts, and in the lab - in fact, 80% of diamonds, most for industrial purposes, are made in labratories.

They come in all colors, with off-white the most common and certain rare colors being extremely valuable, even more so than clear diamonds. Type 1A diamoonds, representing 98% of all finds, have primarily nitrogen impurities and can be clear or pale yellow, because they absorb blue light. Type 1B (0.1%) have more diffuse nitrogen impurities and absorb green light as well, leading to darker yellow and brown colors.

Type IIA diamonds are about 2% of finds and have few impurities, but have small misalignments in the tetrahedral crystal matrix, leading to colors like red, pink, yellow, orange, brown, and even purple. Type IIB, about 0.1%, have boron and nitrogen impurities which absorb red, orange and yellow light, leading to clear and grey diamonds, plus of course beautiful blues like the Hope Diamond.

Radiation, either from a natural nuclear reactor or an artificial source, will turn various greens and blue regardless of diamond type. This is because 12C atoms in the diamond turn to 13C and 14C, which absorb different wavelengths and thus show the different color.

Natural blue diamonds, though not the radioactivity-created ones, are semiconductors due to the boron impurities. Artificial diamonds are also being investigated for possible uses as electrodes for DNA manipulation, radioactivity detectors, high-power switches, detectors for redox reactions, and electrodes for situations that would destroy other electrodes. In addition, it can be doped like any other semiconductor, creating high-temperature transistors, high-frequency field-effect transistors, UV LEDs, and other high-demand, high-energy applications.

Diamonds are generally known as the hardest thing on the planet. However, there is one thing that is harder: more diamonds! Or more exactly, diamond nanorods.

Coming next: other strange Carbon compounds.

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