Lab-grown Synthetic Diamond are gaining popularity among younger consumers due to their lower prices and ethical sourcing. Even the largest diamond mining company, De Beers, now offers a line of lab-grown jewelry called Lightbox.
Scientists figured out how to create diamonds in the laboratory by pressing graphite at high temperatures and pressures. The resulting crystals are pure carbon and have the same physical properties as natural diamonds. The HPHT process replicates the pressure and temperature conditions under which Synthetic Diamonds form naturally beneath the earth, over thousands of years. It does so in a fraction of the time. It requires feeding varying amounts of gases into a chamber and energizing them. The gasses always include a carbon source, most commonly methane, and ultra-high purity hydrogen at a ratio of 1:99. Hydrogen is essential as it selectively etches away non-diamond carbon atoms from the substrate. Manufacturers also use a heat torch to exothermically convert process gas into the ionized plasma used to grow the Synthetic Diamond. Then, energy breaks into the chemical bonds and builds up the diamond layer by layer. High-quality CVD diamonds require careful control of the process parameters including pressure, temperature, and gas composition. This can only be achieved with accurate and reliable instruments, like a gas chromatograph and a trace nitrogen analyzer. Using these instruments helps manufacturers maintain a high-quality product and reduce the risk of contamination. For nearly 150 years scientists, often dedicating their entire professional lives, tried to convert graphite into diamond using various methods. These included crystallization out of a carbon rich liquid, chemical decomposition of graphite under high applied pressures, bombardment with ion beams, quenching of graphite oversaturated liquid iron and more. More recently, the Gemesis Corporation of Sarasota, Florida has marketed colorless CVD diamonds. GIA has evaluated several of these stones, and found them to be F-G on the 4Cs scale, with one graded I. These Synthetic Diamonds were subjected to standard gemological tests, including spectral analysis that reads the diamond’s unique ‘signature’. It is this spectral fingerprint that allows scientists to tell a lab grown diamond from natural and other synthetic gemstones. Along with CVD, a third method of producing diamonds is through detonation of carbon-containing explosives, known as detonation synthesis. Lab-created diamonds can be differentiated from mined diamond by the way light is dispersed through them. When viewed between polarized filters, mined diamonds exhibit a bright mosaic pattern or crosshatched structure called strain. In contrast, CVD diamonds display either no strain or a weak banded pattern that is characteristic of the growth process. The process for growing Synthetic Diamonds is also known as CVD, or chemical vapor deposition. To grow diamonds, scientists feed a carbon seed into a chamber and apply intense heat and pressure. The goal is to transform the seed into a pure crystalized diamond. Lab-created diamonds are pure crystallized carbon diamonds with the same chemical and physical properties as earth-mined diamonds. They are not to be confused with diamond simulants, which are imitations made of superficially similar non-diamond materials. Some people mistakenly believe that lab-created diamonds are fake or low quality, whereas GIA has conducted extensive testing on these diamonds to verify their authenticity and find them to be exactly the same as mined diamonds. In fact, if a Synthetic Diamond is lab-created, it can be identified by its telltale spectral signature and by the fact that it does not show the same characteristic strain pattern seen in natural diamonds when examined under crossed polarized light.
0 Comments
Leave a Reply. |
AuthorAnjali Pawar Categories
All
|