By: Dave Mosher, Life's Little Mysteries Contributor
The first synthetic method is called high pressure, high temperature (HPHT for short). It’s the closest thing to the diamond-producing bowels of the Earth, subjecting graphite (yes, the stuff in a No. 2 pencil, which is made from pure carbon) to intense pressure and heat. Tiny anvils in an HPHT machine squeeze down on the graphite as intense electricity zaps it, producing a gem-quality diamond in just a few days. These diamonds, however, aren’t as pure as natural diamonds because a metallic solution is mixed in with the graphite.
The other diamond-producing method — called chemical vapor deposition — turns its back on intense pressure but cranks out diamonds more flawless than nature can produce. Manufacturers place a piece of diamond into a depressurizing chamber, then zap natural gas with a microwave beam. As the gas is heated to almost 2,000 degrees, carbon atoms “rain” down onto the diamond in the chamber and stick to it, growing a perfect sheet of diamond overnight.
While De Beers isn’t happy with its new competitors, manufacturers have something to be excited about: At temperatures that would melt silicon wafers, sheets of synthetic diamond stay rock-hard.