synthetic diamonds characteristics

Lux is a chemical engineer whose company, the Gemesis Corp., turns out thousands of gem-quality yellow diamonds every month from a factory in Florida, US. Gem snobs may never go for them. 

But they’re not fakes—no cheap cubic zirconias, no moissanites these. 

Synthetic diamonds have a nice ring to them

Posted online: Sunday, March 04, 2007 at indianexpress.com

Lux is a 21st century alchemist who is turning pure carbon into real diamonds, squeezing it into sturdy carbon crystals under intense heat and pressure inside his machines.

That’s how nature made diamonds, billions of years ago, deep beneath the Earth’s crust. Cut and polished, natural diamonds are among the most beautiful and durable gemstones in the world. But they can also be frighteningly expensive.

Gemesis Corp. is one of three US-based manufacturers now producing “cultured” or “created” diamonds. They are chemically, physically and optically identical to natural diamonds, and no more “synthetic” than a baby conceived by in-vitro fertilisation.

Experienced gemologists can tell the difference, but consumers find them indistinguishable from the natural stones, except for the price tag—only a half to a tenth of the price of comparable mined stones.

Gemesis adds a new diamond growth chamber to its factory floor every few days and should approach a thousand machines in the coming year, Lux said, creating “a virtual diamond mine here in Florida.”

By way of contrast, natural diamonds formed as long as 3.3 billion years ago, under intense pressure and temperatures more than 90 miles below the Earth’s surface. There, atoms of carbon reorganized themselves into cubes, and the cubes grew into crystals.

Carried back to the surface by volcanic eruptions, then exposed by erosion and mining, they’ve been prized throughout history for their beauty and durability.

According to the gem institute, most natural diamond crystals are “octohedrons,” a pair of four-sided pyramids joined at the base. Most are colourless, too, but many contain traces of other elements and impurities that lend them a variety of “fancy” hues such as yellow, orange, pink and blue.

Although scientists first produced man-made diamonds a century ago, it was not until 1954 that General Electric patented the first commercially viable process. One of the first to pursue man-made, gem-quality diamonds was Carroll Chatham of California’s Chatham Created Gems Inc., who grew the first man-made emerald in 1938.

In 1992, with the collapse of Soviet communism, his son and heir, Thomas Chatham, visited Russia, where he bought diamond-making technology originally developed to serve Soviet military and aerospace needs.

Meanwhile, Gemesis founder Carter Clarke followed Chatham to Russia looking for other business opportunities, but leaped at the chance to buy diamond-making technology. He brought the Russian engineers and their diamond-making machines back to Florida, where he and a scientist at the University of Florida spent the next decade trying to perfect the machinery.

They succeeded. Today, Gemesis’ 4-ft-high, HPHT diamond machines start with a natural diamond “seed” that’s slipped inside a pressure capsule two feet in diameter—and secured against the internal pressure with a clamping collar four feet wide. The capsule is filled with a “flux” of pure carbon dissolved in a molten metal solvent, and brought to 2,500 degrees Fahrenheit under 850,000 pounds of pressure per square inch.

“It’s like growing sugar crystals in water,” explained a Gemesis executive. The carbon at the hotter end of the chamber migrates to the cooler end and attaches itself to the seed diamond, growing the crystal atom by atom.

Each of the factory’s US-made growth chambers spits out a gem-quality diamond every two to three days. The Gemesis stones are cut, polished and mounted by middlemen, then retailed in a handful stores in the US and South Africa.

—LAT-WP / Frank D. Roylance