chemical vapor deposition (CVD) diamonds- Growing diamonds (colorless and pure)

One of Apollo’s made diamonds.

“When I came in Monday, I couldn’t see the (stone) in the beaker,” Linares says. The diamond was colorless and pure. “That’s when I realized we could do gemstones.”

Apollo Diamond is making real diamonds through a process called chemical vapor deposition (CVD). Here is an explanation of the process:

(1) A slice of diamond is placed flat inside a chamber. Hydrogen and hydrocarbon gases are injected and heated to thousands of degrees at the right pressure.
(2) Carbon atoms land on the diamond slice and replicate the crystal’s structure, the way a drop of water merges seamlessly into a pool of water. The diamond grows thicker and taller. Growing a 5 carat diamond can take a week.
(3) The top can be sliced off and cut into gems. Or the diamond can be cut into thin wafers for computer chips or other uses. Part of the slice is returned to the chamber to make the next diamond.

“We basically grow our own raw material,” says Apollo president Bryant Linares.

Source: Apollo Diamond

Two different paths to diamonds

In 1955, General Electric figured out how to use room-size machines to put carbon under extremely high pressure and make diamond dust and chips. The diamond material wasn’t pure or big enough for gems or digital technology. But it had industrial uses, such as diamond-tipped saws. Such saws made it possible, for instance, to cut granite into countertops.

In the ensuing decades, companies and inventors tried to make bigger, better diamonds. But they didn’t get far. By the 1990s, researchers were focused on two different paths to diamonds.

One was brute force. Some Russians became pretty good at it, and their machines were eventually brought to Florida by Gemesis. That company now crushes carbon under 58,000 atmospheres of pressure at 2,300 degrees Fahrenheit, until the stuff crystallizes into yellowish diamonds. The stones are attractive for jewelry but not pure enough for digital technology. Gemesis sells its gems through retailers at around $5,000 per carat. A mined yellow diamond can cost four times more.

The other process is called chemical vapor deposition, or CVD. It’s more subtle. It uses a combination of carbon gases, temperature and pressure that, Linares says, re-creates conditions present at the beginning of the universe. Atoms from the vapor land on a tiny diamond chip placed in the chamber. Then the vapor particles take on the structure of that diamond — growing the diamond, atom by atom, into a much bigger diamond.

Read the whole interesting article here: USA TODAY – Thanks to Charles for sending this in!
Another related article here: www.wired.com