Nature forms the diamonds that come from mines by exerting tremendous pressure. Until comparative recently, human beings didn’t know how to mimic that process. Today, however, we can make synthetic diamonds. Manmade diamonds are real diamonds in every respect, made of the same carbon as those found underground and the same with regard to their physical, chemical, and optical properties. The only difference is that lab diamonds (sometimes called “synthetic” diamonds although that term’s not really accurate) are the products of human ingenuity.
Mined diamonds formed deep underground 1 to 3 billion years ago. The process probably started with carbon dioxide buried about 100 miles underground. This carbon dioxide experienced heat in excess of 2200 degrees Fahrenheit and pressure of about 727,000 pounds per square inch. That turned it into diamonds, and volcano activity then carried the stones closer to the surface of the Earth.
The process of making artificial diamonds is in many ways analogous. Technically, there are two methods, High Pressure-High Temperature (HPHT) and Chemical Vapor Deposition (CVD,) There are three methods for performing the HPHT methods, the belt press, the cubic press, and the split-sphere (BARS) press. Each of these yields high pressure and high temperatures conducive to diamond growth. At the start, technicians place a small diamond in carbon. They then subject it to pressures of about 15 million pounds per square inch and temperatures around 1500 degrees Celsius. As a result, the carbon around the small diamond also turns to diamond, and the stone is then carefully cooled.
The CVD process begins with a thin slice of diamond, often an HPHT diamond. That starter seed goes into a sealed chamber that heats it to around 800 degrees Celsius and subjects it to pressures around 1.5 million pounds per square inch.
The chamber is full of a carbon-rich gas (methane, for example) that’s ionized into plasma. (The technology is similar to that utilized in microwaves and lasers.) That breaks the molecular bonds in the gases, releasing pure carbon that crystalizes around the starter seed.
As we’ve already mentioned, mined diamonds and artificial diamonds share the same physical, chemical, and optical properties. That means you won’t be able to tell the difference just by looking. Even jewelers have considerable trouble distinguishing.
People actually can tell, though, by sophisticated scientific testing. There are two tests that will do the job.
The first is a Type IIa Test. This determines how pure the carbon in a diamond is. A Type IIa diamond is the purest type, and only 2% of mined diamonds fall into this category. Nearly all lab grown diamonds do, so it’s a pretty safe bet that if the test indicates you’re evaluating a Type IIa diamond, it’s manmade.
The second is a radiation test performed with specialized equipment. Both HPHT and CVD diamonds emit specific patterns of light across the visible and ultraviolent parts of the spectrum when subjected to this test.
Since it’s so difficult to tell the difference between mined diamonds and lab grown diamonds, some consumers might worry that they’ll be the sold the latter in the guise of the former. Reputable jewelers don’t do that, though, and some manmade diamonds even carry laser inscriptions on the girdle to indicate that they came from a lab. In any case, when a diamond is graded, the grading report indicates whether the stone is mined or artificial.
Manmade diamonds are graded in exactly the same way as mined ones. Diamond grading involves several gemologists looking independently at a stone. They generally grade it on the so-called “4 c’s,” carat, clarity, color, and cut, although some labs apply other criteria. The final grade is presents the average of the individual evaluations.
Grading labs tend to differ somewhat in their assessments. At Karat Jewelry, we use a lab we have confidence in to provide our Hinsdale, IL, customers with what we consider to be highly accurate grading. We encourage patrons to ask any questions they may have about a particular diamond’s grade and what factors determined it.
There are two main benefits to buying lab diamonds.
First, they’re cheaper than mined stones of the same grade. That, of course, doesn’t mean you can pick them up for pennies. Any diamond will run you a fairly significant amount of money. In fact, the cost of manufacturing a diamond in a lab and pulling one out of the ground are approximately the same. Cutting, polishing, and inspection cost the same. But the difference is in the supply chains.
Lab diamonds have a relatively short supply chain. Mined diamonds have much longer ones consisting of miners, distributors, cutters, polishers, jewelry manufacturers, and finally retailers. That makes a significant difference.
Second, lab grown diamonds are more environmentally friendly. Many diamond mining companies are trying to limit any adverse impact, but even so, the fact remains that the mining is rough on the environment. In contrast, it takes less energy to make a diamond in a lab than it does to pull it out of the ground. The creators of lab grown diamonds are actually motivated to use as little energy as possible to reduce their costs.
With all that said, some customers simply prefer mined diamonds. They just prefer them, or they find an allure in the idea that a stone came from Nature that an artificial diamond simply doesn’t deliver. Ultimately, only you can decide which diamond is right for you. Visit Karat Jewelry at our Hinsdale, IL, location and we’ll be happy to help you explore your options.
9 E 1st St., Hinsdale, IL 60521
Tel: 312 854 3056 Fax: 312 854 3057
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