Lab created diamonds are nothing new to the diamond industry; in fact, they turned out to be the best solution for buying readily available jewelry that completely satisfies customers’ desires and of course, their budget. Man-made, lab-grown, synthetic or cultivated, call ’em whatever you like, but the truth is, these breathtaking stones have taken our craftsmanship to a whole new level and today, we cannot imagine creating fine jewelry pieces without them.
They are not just beautiful, sparkling and cost-effective; they are eco-friendly too and this feature is simply priceless. Mother Nature must be grateful to mankind for having invented lab created diamonds; mankind, on the flip side, is happy for having them as an “ingredient” for making conflict-free jewelry. Stay with us to learn how these precious stones are made.
The idea to protect the natural diamond treasury by creating synthetic diamond counterparts first appeared in 1879. According to the gemological reports, only a few attempts were made and ended unsuccessfully. During the 1940s, a more advanced research began in the US, the Soviet Union and Sweden about growing diamonds in a laboratory by using HPHT (high-pressure high-temperature) and CVD (chemical vapor deposition) methods. In 1953, the first synthetic diamond was officially made, thus becoming a groundbreaking discovery that set a milestone in the diamond industry. A few other techniques were developed later, but it was only in the past decade that scientists were able to perfect the making of diamond simulants, by using high-tech equipment and lots of enriched knowledge. Therefore, it won’t be wrong to say that today’s lab created diamonds are way more refined and superior than earth-mined diamonds.
THE MAKING OF
Lab created diamonds are grown in specialized diamond labs under highly controlled conditions that simulate the environment in which Earth-mined diamonds occur. Actually, this is what makes a man-made diamond have the same chemical and optical properties as its mined counterpart.
The two most common methods to produce synthetic diamonds are HPHT and CVD (the ones we mentioned earlier). Sometimes, there is a combination of multiple techniques in order to obtain fine-quality stones (both colorless and fancy-colored). Next, we are going to explain how lab created diamonds are made with each of these methods respectively.
› HPHT (HIGH-PRESSURE HIGH-TEMPERATURE)
This process basically re-creates the natural process in which diamonds occur in the depths of Earth’s crust under a pressure of 60,000 atm and a temperature of more than 4500°F. The HPHT method requires impeccably controlled conditions to grow a diamond, because if any shift happens, the entire process will fail. Therefore, the so-called “growth cells” have to contain all of the required elements (diamond seed, catalyst mixture of metals and high-quality graphite).
Once set, the growth cell is set in an HPHT machine, (also called “chamber”) established to provide the aforementioned levels of pressure and temperature. The catalyst solution is the first one to react to these conditions by dissolving. What happens next is the cooling process. Usually, it takes a couple of business days for the carbon atoms to start building upon the diamond seed and when the growth process is finished, the cell is taken out of the HPHT chamber. The outcome is a fresh, pure-carbon diamond that is ready to be cut and polished. (Please note that cubic zirconia is NOT a diamond, even though it is artificially made and it has a few diamond-like features).
Here is the list of commonly used tools during the HPHT process of making lab created diamonds:
● Bars Press
This tool employs inner and outer anvils that provide the growth cell with hydraulic pressure. So far, it has been the best tool for making gem-quality diamonds.
● Belt Press
This is another type of pressure tool that can create several diamonds in only one cycle. It usually features two large anvils that make the necessary pressure for the growth cell. The belt press is used for making gem-quality diamonds, but also classic diamonds and diamond powder.
● Cubic Press
This tool finds its use in the making of diamond powder for industrial purposes only. It is large and it features six anvils that provide the necessary pressure for the growth cell.
› CVD (CHEMICAL VAPOR DEPOSITION)
This process allows the creation of gem-quality diamonds, as well as semiconductors and optics. During this process, the growth-cell chamber is filled with gases rich in carbon. These gases are heated at a high temperature in order to break apart and separate the carbon atoms. The carbon-atom particles form layers on a diamond substrate, which results in making a rough diamond crystal. It takes between 5 and 10 weeks for a CVD process to be completed.
THE COLOR WHEEL OF LAB CREATED DIAMONDS
There are several colors in which lab created diamonds are available on today’s market:
Colorless diamonds are pure classic and they are admired for their brilliant, eye-clean look. However, most diamonds (natural and synthetic) have impurities in their crystal structure, due to the presence of nitrogen. Actually, it is nitrogen that causes the yellow tints of a diamond. The practice is showing that almost every diamond, regardless of its origin, starts as a yellow-tinted gem. In nature, it takes up to million years for the nitrogen atoms to split within the stone and make it shine crystally white. In a high-controlled laboratory, on the other hand, this process does not last that long, obviously; it takes only a few weeks and the results are absolutely the same.
When growing a white diamond, the most important thing is to keep the pressure and temperature consistent all the time. If not, the diamond may grow with heavy inclusions and that is certainly not a desirable feature for colorless diamonds. The process of splitting nitrogen and boron atoms within the growth cell of the diamond in order to make it white, normally lasts two weeks. This is the normal process for colorless lab created diamonds that weigh 1 carat.
White diamonds are extremely versatile to be worked with, because their “go-with-everything” look allows to carve them in practically all shapes. Most white lab-grown diamonds are cut manually and the ultimate goal is to maximize their fire and brilliance. They are especially desired for engagement rings and bridal sets.
The color palette of yellow lab created diamonds ranges from pale to vivid yellow nuances. You just found out that their “yellowness” comes from the amount of nitrogen in the growth cell, which must be controlled during the entire process to give the diamond the desired yellow hue. Obviously, more nitrogen means more intense yellow color. Orange diamonds are also part of this category and they are grown in a special molten solution. When the solvent blends with the nitrogen atoms trapped within the growth cell, the diamond gets an orangish-yellow color.
Unlike colorless lab created diamonds, yellow diamonds grow from earliest to final stage in only six days. Most of them come in sizes ranging from 1 to 2 carats.
Rough, unfinished yellow diamonds have an octahedral shape that is further molded into the desired final look. The most popular shapes for yellow diamonds are cushion, princess, asscher, radiant and emerald. They can be often seen in designs of vintage-inspired jewelry creations.
Just like the other types of diamond colors, blue diamonds made in a laboratory feature the same physical and optical properties as blue diamonds found in nature. Their color varies from light to intense blue, which comes as a result of the boron presence. Again, the amount of boron is precisely controlled to achieve the desired blue hue that is reflecting when light enters the stone.
One cycle of synthetic blue-diamond production lasts 7 to 10 days for a 1-carat stone. The truth is, boron makes the diamond grow faster than nitrogen and that is why these diamonds can be found in greater quantities on the market than white-colored ones.
While in the growth cell, the synthetic blue diamond has a hexa-cubic form. That is why these diamonds offer the best look in corner shapes, such as cushion, asscher, radiant and emerald.
What makes pink diamonds different from the other color types is that they get their color after the growing process. Hence, they undergo a particular post-growth procedure called “irradiation and annealing”. A yellow diamond is used as a base to make a pink-colored one. The irradiation treatment includes electrons and neutrons that develop a new color center. The next step is annealing to perfect the changes made with irradiation and give the diamond its final color appearance.
Lab created diamonds in pink color are usually given the same shapes as yellow diamonds (cushion, princess, asscher, radiant and emerald). The round shape also looks good on these diamonds. Elongated shapes, like marquise, oval and pear are commonly avoided, due to the square shape in which the rough pink diamond grows.
The clarity grade of pink lab created diamonds depends on the intensity of the color. Hence, those that are more saturated have a lower clarity grade than those that are showcasing a lighter pink color. Clarity is the main feature that determines the price of pink diamonds, but as long as they are eye-clean, consumers are ensured a quality purchase.