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FAQ

FAQs?

Regular Questions & Answers Presented Here

CVD stands for chemical vapor deposition.

On vast areas (>100 cm2), diamond is usually placed at growth rates within 0.1 and 10 microns per hour. Hence it is a prolonged process. For small areas (<1 cm2), much bigger growth rates (>100 microns per hour) have been confirmed.

CVD Diamond is one type of synthetic diamond which prepared by CVD technique in lab atmosphere.

Diamond can be placed on various materials similar to diamond, silicon, tungsten, molybdenum, silicon carbide, silicon nitride, quartz glass, bonded carbide, etc. The main elements are: the material must be able to confront high temperatures, the stimulated process gas must not attack it, and it must not terminate carbon.

Diamonds are like coal or graphite of carbon. The main difference is the design of the carbon atoms in the material (i.e., in the crystal lattice). Unfortunately, graphite is the more stable carbon form, and therefore diamond is costly. To transform graphite into diamond high pressure and high temperatures (HPHT) must be implemented. Under those conditions, the diamond becomes the more durable carbon form. This is the basis of the HPHT growth technique stated in the 1950s. The possibility to deposit diamond from the gas phase (CVD) has been found later in the 1970/1980s. For CVD diamond, a carbon-containing gas is decayed, and the carbon atoms are placed on a surface. By proper conditions, the growth of diamond crystals can be improved, and the growth of graphite is overcome.

We can increase the size of the crystal by depositing diamond on the diamond crystal. After this process, new carbon atoms are added to the old diamond lattice, which is called homoepitaxy. On non-diamond substrates, pretreatment of the surface is required to allow diamond formation. E.g., by polishing a silicon substrate with diamond powder, tiny diamond particles remain on the surface that works as seeds for the growth of small diamond crystals. During the deposition, the size of these crystals grows until they form a continuous compact layer of tiny diamond crystals (grains) – i.e., poly crystalline diamond.

For CVD diamond atomic hydrogen plays a vital role. It is taken by dividing hydrogen molecules (H2). So, what we require is a process gas that has mainly of hydrogen (>90 %) and a gas activation, e.g., an extreme plasma or a hot fiber, to split up the hydrogen molecules. Atomic hydrogen is known to etch graphite selectively and to split up double bonds, thus turning graphitic bonds into diamond bonds.

Thin diamond films can be prepared on areas as large as 0.5 m2 using an array of hot threads for gas activation. Diamond-coated silicon wafers are generally made by microwave plasma displacement. Here the maximum wafer diameter is within 4” (2.45 GHz excitation) and 8” (915 MHz excitation). Diamond disks are gained by growing a thick diamond zone on a substrate and by separating the substrate after that. The standard size of these disks is 1-12 cm in diameter. Finally, the size of single diamond crystals depends mostly on the size of the seed crystal used. Sadly, the availability of wide-area seed crystals is minimal.

Mostly a mixture of methane and hydrogen.

Free-standing diamond layers mounted on silicon support have been demonstrated with depths as low as 30 nm. On another end of the scale, diamond disks with more than 2 mm depth are commercially available.

It require above 700-900°C. lower temperature are also possible but it strongly slow down the growth rates.

Usually, the grain size is in the sub-micron range at the start of diamond growth. With increasing thickness, the grains tend larger. Often, the grain size at the growing surface of a diamond film is about 10 % of the film thickness.

Usually, the grain size is in the sub-micron range at the start of diamond growth. With increasing thickness, the grains tend larger. Often, the grain size at the growing surface of a diamond film is about 10 % of the film thickness.

Fact: Though they may be called ‘synthetic’ diamonds, they aren’t. Synthetic is defined as a material or chemical created to imitate a natural product. There are of course synthetic diamonds out there, but lab-grown diamonds are different and nothing like them. These man-made diamonds are 100% carbon and not many people know that this form is grown from the tiny carbon seeds of pre-existing diamonds. Synthetic Diamonds such as Cubic Zirconia (CZ) and moissanite are made of zirconium oxide and Silicon Carbide respectively. But moissanite and cubic zirconia are chemically different than Diamonds (Earth-mined and Lab-grown diamonds), and don't quite look the same as a result; cubic zirconia has less brilliance, or sparkle, then diamonds and moissanite produces a blurred effect called a double refraction.

Fact: There is no difference between an earth-mined or a lab-grown diamond. When you freeze water, it becomes ice. But isn’t the chemical composition of ice the same as water? Similarly, whether the diamond forms deep under the surface of the earth owing to the intense heat and pressure, or if the diamond is grown in a lab that mimics the very same conditions, the quality and authenticity remain the same.

Fact: In fact, it is extremely difficult to find natural diamonds with the purity comparable to a lab-grown diamonds. Only 2% of diamonds found under the earth’s surface reach the level of purity generally expected from cultured diamonds.

Fact: Have you ever wondered how much work goes into mining the earth’s surface to uncover diamonds? A lot. Natural diamonds are formed more than 150 Km below the surface of the earth. And after the effort to get there, the diamonds have to be sorted, cut and polished. That’s a lot of work. Whereas in a laboratory environment, the process of digging and mining gets eliminated. The next course of the diamonds being created exactly under the same conditions, however, remains. Also, the cost of cutting and polishing a rough diamond into a saleable quality diamond gemstone will always cost the same money. As the process to artificially grow diamonds is one of the most difficult and precise manufacturing techniques that can only be performed by skilled PHD, Physicians and Chemist. It is unlikely that the manufacturing cost of these diamonds will ever go down. Each MPCVD reactors cost more than half a million dollars and needs continues Research & Development Expenditure which also increases investment.

Fact: Lab-grown diamonds are conflict-free regardless of where they are grown. They are sourced from first world countries where they are treated and cut in a controlled modern-day lab environment. Whereas, natural diamonds, on the other hand, have to be vetted to ensure that they are conflict-free.

Fact: Though the ‘eco-friendliness’ of lab-grown diamonds is debatable, they are still far better than natural diamonds. Natural diamonds are extracted by mining the earth’s surface. Mining leads to the degradation of the environment in many ways. Soil erosion, displacement of biodiversity etc., are some of the commonly seen hazardous impacts. Lab-grown diamonds barely affect our environment. Thus to conclude we say, it is important that when making a purchase, diamond shoppers along with looking for the aesthetic value of a diamond should also try and find out where these shiny stones were sourced from. It is important to also become aware of the environmental consequences of such stones.

Fact: A lab diamond has the same physical, chemical and optical properties of a mined diamond. It will not change color. It will not change appearance. It will look exactly the same in a million years as it does the day it’s polished. In fact, if you placed your lab diamond engagement ring in a lab vat of concentrated hydrochloric acid and nitric acid the gold or platinum would dissolve but your diamonds would just get a good cleaning! The only ways that a lab diamond could be damaged is the exact same way that a mined diamond could be damaged. It is possible that the reason that jewelers promote this misinformation is that some cheaply produced cubic zirconia will oxidize and get cloudy over time. Cubic zirconia (a.k.a American Diamond) is not a diamond.

Fact: Lab-grown diamonds are relatively new to the marketplace so therefore must find their place in the resale chain. However, Created Emeralds and Rubies have a 50+ year history and have a resale value. Go to Ebay.com and pull up Chatham Emerald or Ruby and you will find many pieces of jewelry selling for thousands of dollars. Moreover, the machinery required to duplicate the conditions 100 miles below the Earth’s surface is very expensive, each press costing between USD 500,000 and USD 1,000,000 each plus infrastructure. Mined diamonds are “free”…you can just pick them off the ground in some areas but all the “added value” comes from marketing expenses added on. On average, natural diamond costs USD 200 per carat to mine from the earth! Not so Lab-grown. We each have our own up-front costs.

Fact: Unlike mined diamond, Which is exchanged many hands before it is set on Jewellery. Lab-grown diamonds have a short and more transparent supply chain. All our Diamonds are guaranteed to be replaced or changed.

Fact: This is nonsense! Not only are diamonds in plentiful supply in numerous different parts of the world, but there are also warehouses full of them waiting to be sold. The perceived rarity is only due to a conscious decision to restrict the market supply, playing on diamonds’ scarcity several hundred years ago.