Education on the HPHT Lab Grown Diamond and Its Cost
- LONITÉ
- Feb 21, 2022
- 14 min read
Updated: Sep 18, 2023
TABLE OF CONTENT
Education on the HPHT Lab Grown Diamond and its Cost
Lab grown diamonds, commonly known as lab-created or man-made diamonds, have continued to gain popularity. Not only are they captivating and beautiful, but they are also affordable and ethical. And of course, as the name suggests, these diamonds are made in a controlled laboratory environment.
Lab grown diamonds constitute up to 3% of the global market of $1.74 billion and are made using different processes, including HPHT (High Pressure High Temperature), CVD (Chemical Vapor Deposition), ultrasound cavitation, and detonation. By 2035, their market share is expected to grow to up to $13.4 billion.
Lab Grown Diamonds Are Not Artificial, but Real Diamonds
When people talk about lab grown or HPHT diamonds, they often wonder, “Are HPHT diamonds considered real diamonds?” The answer is yes.
Although natural diamonds and lab grown diamonds have different origins, their structure is exactly similar. For example HPHT diamonds are made from pure carbon crystallized in an isotropic 3D form and the resulting gems are similar to those mined from the earth’s crust.
GIA has studied lab grown diamonds for over 30 years and according to them, “their chemical and physical properties correspond very closely to those of natural diamonds.” For this reason, scientists believe that lab grown diamonds are not imitations or stimulants, but real diamonds that can be easily identified by trained gemologists using standard gem-testing equipment.
When Was the First Lab Grown Diamond Made?
In 1797, it was discovered that diamonds were made of pure carbon. This led scientists to believe that the process that created natural diamonds could easily be replicated in labs. However, there was no report of individuals or companies creating diamonds in the laboratory until 1879 when James Ballantine Hannay reported developments using a method that involved heating charcoal and iron inside a carbon cubicle in a furnace. Modern testing later proved that the remaining samples from his experiments were, in fact, natural diamonds instead of synthetic.
Over the years, scientists continued improving existing processes and developing new ones. Some of these scientists include; Feerdinard Henri Moissan, who attempted to make lab grown diamonds with an electric arc furnace in 1893, Sir William Crookes, who used 190000 psi enclosed cordite explosions to create radium bromide diamonds in 1909 and Otto Ruff, who, in 1917, claimed to produce diamonds with a diameter of up to 7 mm but later retracted his statement.
In 1926, Dr. J Willard Hershey from McPherson College replicated Ruff’s and Moissan’s experiments of producing lab grown diamonds. Meanwhile, Sir Charles Arganon Persons also devoted 40 years of his life, from 1882 to 1922, attempting to reproduce the experiments of Hannay and Moissan. Along the way, he adapted his own processes too and all his resulting samples were preserved for further analysis by an independent party.
The most significant breakthrough in the industry of lab grown diamonds took place in December 1954, when an America company named GE created the first-ever batch of industrial-grown diamonds.
Synthetic Diamonds vs. Natural Diamonds
No two diamonds are ever exactly alike, and this stands true for both natural and lab grown diamonds. However, both of these have their own similarities as well as prominent differences that make distinguishing them easier. Let’s have a look.
Similarities
When seen by a native and inexperienced eye, lab grown diamonds appear to be the same as natural diamonds. Primarily, this is because their physical and optical properties, chemical composition, and crystal structure are the same. For this reason, only trained gemologists can distinguish between them.
The majority of natural diamonds have trace amounts of other elements, including nitrogen, which gives it a yellow color or boron, which provides them with a blue color and hydrogen. Similarly, lab grown diamonds made with the CVD method involves the breakdown of molecules of carbon-rich gas like methane into hydrogen and carbon atoms. For this reason, traces of hydrogen can be found in CVD lab grown diamonds. In the case of HPHT diamonds, traces of nitrogen give the gem a naturally amber color.
In addition, both lab-created and natural diamonds alike have inclusions that impact their clarity. Natural diamonds contain bits of foreign material that was trapped in the still-forming diamonds years ago and this can manifest as metallic inclusions for the case of lab grown diamonds. These inclusions can be identified with a 10x magnification.
Differences between Lab Grown Diamonds and Natural Diamonds
Time: Lab grown diamonds take roughly 6 to 9 months to develop in a lab. Meanwhile, natural diamonds that are close enough to the earth’s surface to be mined today formed roughly 1 billion to 3.3 billion years ago.
Colors: Lab grown diamonds can be grown in white, green, pink, yellow, and blue and are generally found with color grades that range from K grade to D grades. Some kinds of lab-created diamonds are color-treated for example CVD diamonds that have a brown color are decolorized through a treatment process to make them almost or entirely colorless.
Meanwhile, natural diamonds can be found in all colors imaginable with an infinite number of saturation levels, tonality, and hues. The colors occur due to the impurities like nitrogen molecules that get trapped in the diamond lattice. Different trace chemicals in pure carbon cause different saturation levels and, in turn, different colors. The most common color for diamonds is white, while rarer colors include vivid blue, pink, and fancy yellow.
Place of formation: Natural diamonds are formed deep within the earth’s mantle under conditions of high temperature and high pressure. Due to volcanic activity, diamonds are carried to the surface where they lay in a volcanic rock formation called kimberlite pipes, ready to be mined. However, roughly only 5% of the kimberlite pipes have enough diamonds to make them feasible to mine.
On the other hand, lab grown diamonds are made in the laboratory, as the name suggests.
How Are Lab Grown Diamonds Made?
HPHT Diamond Process
High Pressure High Temperature is the most common process used to create lab grown diamonds. It mimics the natural process, which combines both high temperature and high pressure conditions to make natural diamonds in the mantle of the earth.
A similar environment of pressure up to 60000 BAR and temperatures of up to 3000K is created in the lab in order to turn carbon into diamonds. LONITE uses the HPHT diamond process to create all its lab grown gems.
The HPHT diamond process has three main press designs that are used for supplying the temperature and pressure necessary for producing lab grown diamonds. These are:
a. Belt Press
Both the lower and upper anvils supply a pressure load to the cylindrical inner cell. The internal pressure is radially confined by a belt of pre-stressed steel bands. The anvils also function as electrodes to provide electric current to the compressed cell.
b. Cubic Press
A cubic press has six anvils that provide pressure into all the faces of a cube-shaped volume simultaneously. Typically, a cubic press is smaller than a belt press but it is just as capable of achieving the temperature and pressure necessary for creating lab grown diamonds.
c. Split-sphere (BARS) Press
A synthesis capsule, which is a cylindrical capsule made of ceramic measuring 2 cm cube in size, is placed at the center of the BARS device. This is believed to be the most economical, efficient, and compact method.
2. CVD
CVD or Chemical Vapor Deposition is another method used for making lab grown diamonds. This method involves growing diamonds from a mixture of hydrocarbon gases. The simplicity and flexibility of CVD setups make it one of the most common methods.
CVD diamond growth also ensures several advantages such as the ability to grow diamonds on various substrates and over large areas as well as control over chemical impurities. Ultimately, CVD allows control over the properties of the resulting lab grown diamond.
Also, this process doesn’t need high pressure since growth of the man-made diamond usually takes place at pressures of under 27 kPa.
3. Detonation of Explosives
Lab grown or man-made diamonds can also be made using the detonation of explosives. By detonating some carbon-containing explosives within a metal chamber, it is possible to form diamond nanocrystals measuring up to 5 nm in diameter. These nanocrystals are termed as detonation nanodiamonds.
During this explosion, the temperature and pressure in the chamber becomes so high that they can convert the carbon from the explosives to diamonds.
4. Ultrasound Cavitation
The last method used for making man-made diamonds is ultrasound cavitation. With this method, micron-sized diamond crystals are made from a suspension of graphite in organic liquid. The suspension is kept at room temperature and atmospheric pressure using ultrasonic cavitation. Perhaps the greatest benefit of this technique is that it needs relatively simple procedures and equipment but it has only been reported by two research groups, and has no industrial use as of 2012.
Is an HPHT Lab Grown Diamond the Same as a CVD Lab Grown Diamond?
HPHT diamonds are not the same as CVD diamonds. Their primary difference lies in the materials and methods used for creating the two.
Whereas the HPHT diamond process involves the use of high temperature and pressure on carbon, the CVD process involves depositing gases such as methane on a diamond seed in order to produce diamonds.
In addition, with HPHT diamonds, it’s quite tricky to produce completely colorless diamonds. The majority of diamonds produced using this method either turn out to be brown or yellowish in color. On the other hand, with CVD, the vacuum chamber just contains hydrogen and carbon, which means that colorless crystals are possible. However, if boron or nitrogen is introduced in the chamber, blue or yellow man-made diamonds can be produced.
Why HPHT Lab Grown Diamonds Are More Environmentally-Friendly
As mentioned earlier, man-made diamonds are created in labs, so there’s more control over the labor processes, plus the energy needed to make them is less. Of course, both lab production and diamond mining require energy usage. This use of energy can have an adverse effect on the environment since excess natural gas and oil resources are used.
However, the amount of energy used for lab grown diamonds is significantly low. One of the greatest producers of natural diamonds requires 80.3 kilowatt-hours for each carat in mining operations. Meanwhile, lab grown diamonds need only about 20-28 kilowatt-hours for each carat.
Secondly, mining natural diamond damages the surrounding environment a lot as well. For instance, if the mine is roughly 2 miles in depth, then all the surrounding earth within that depth will also have to be excavated. To put it into perspective, for 1-carat diamonds, up to 1700 tons of dirt would have to be removed. Moving the excavated dirt also influences the area surrounding the mine since that dirt has to be dropped somewhere. The end result is the land being disturbed; in fact, even waterways and other similar features are removed for mining natural diamonds.
Meanwhile, since man-made diamonds are grown in a lab, manufacturing them won’t affect any land. Manufacturers just have to place carbon in a machine, and it is converted into diamonds after a series of processes. Man-made diamonds have a very minimal impact on the plants, animals, or land.
When compared to natural diamonds, man-made diamonds produce fewer carbon emissions. Since the former needs heavy machinery for excavation and production, the carbon emissions are higher, thus impacting the environment more. For the lab grown diamond process, however, no fossil fuels are needed since most laboratory machines are run by power.
How to Identify Lab Grown Diamonds
Experienced personnel, as well as specialized equipment, are needed for differentiating and identifying man-made diamonds and natural diamonds. There are two institutions that are known for their standards in grading and testing gemstones; one is GIA – the Gemological Institute of America, and the other is IGI – International Gemological Institute.
Generally, it’s possible to differentiate lab grown diamonds based on the following factors;
a) Color Distribution
The HPHT process produces colored lab grown diamonds that usually show uneven coloration. This coloration can easily be noticed with transmitted light with the help of a microscope. For additional clarity, the cut stone can be immersed either in mineral oil or water to minimize the surface reflections.
Lab grown diamonds show color zoning due to the various impurities incorporated in the diamond crystal during its formation process. Examples of such contaminants include nitrogen and boron. Sometimes, natural diamonds also show some color zoning; however, the geometric pattern of the zoning is different than that of HPHT lab grown diamonds. Meanwhile, CVD-grown man-made diamonds typically show even coloration.
b) Graining Patterns
Diamonds have grain inside, almost just like wood does. With specialized equipment, these grain patterns can be evaluated. The observed pattern can then tell the gemologist details of how the diamond was actually formed.
As mentioned earlier, natural diamonds form deep in the earth over millions of years, while lab grown diamonds formed in 6 to 9 months. Therefore, both of them have drastically different growth and graining patterns. Man-made diamonds have a specific grain pattern, which is a confirming indicator.
c) Fluorescence Colors
Man-made diamonds can also be distinguished with the help of special light waves that cause diamonds to glow. Lab grown diamonds glow more brightly than natural diamonds, which is an early indicator.
Another indicator is the color that the stone returns to as the special light waves hit it. Typically, earth-mined diamonds give off a blue color while lab grown diamonds made with the CVD process give off a bright orange color. Similarly, HPHT lab grown diamonds most commonly fluoresce in a turquoise or off-bluish color.
The fluorescence pattern is another indicator. HPHT diamonds have a cross-shaped pattern either on the pavilion or on the crown. Meanwhile, CVD diamonds have a striated pattern when seen through pavilion facets.
d) Metallic Flux Inclusions
HPHT diamonds have inclusions of flux metal. In transmitted light, the metallic flux inclusions appear opaque and black while in reflected light, they have a metallic luster. Plus, the flux metal alloy used for growing diamonds contains elements like cobalt, nickel, and iron. This means that man-made diamonds with large metallic inclusions will be easily attracted to a magnet and can be picked up with it.
Meanwhile, CVD-grown diamonds form in a completely different way, so there are no metallic inclusions.
On the other hand, only some natural diamonds have dark inclusions of graphite or other minerals; however, these don’t have any metallic luster.
e) Strain Patterns
When tested between two polarizing filters placed at ninety-degree angles to each other, natural diamonds show a bright mosaic or crosshatched pattern of strain or interference colors. These arise because of the stresses the diamonds are subjected to under the earth's surface or when it erupts explosively to the earth’s surface.
Man-made diamonds, however, grow in an almost 100% uniform pressure environment with no stress. So, when lab grown diamonds are inspected with polarizing filters, there are either no strain patterns or just a weak banded strain pattern.
f) Inscriptions in the Girdle
Lab grown diamonds usually have a minuscule inscription present on the girdle that labels it as a lab created diamond. Of course, you can’t see this inscription without extensive magnification. Generally, a jeweler’s loupe has 10 x magnifications; however, to see the inscription, you would need up to 30 x magnifications.
The girdle of the diamond is basically its widest part, and the size of the lettering for the inscription will correlate to the girdle’s size. In other words, a thin girdle will have tiny lettering, which is why a 30x magnification loupe is essential.
In most cases, whenever grading labs identify or certify a man-made diamond, they inscribe the girdle, marking it as lab-grown if there is none present. However, if there’s absolutely no inscription on the girdle, even after it has been lab-tested, then you know you’re looking at a real diamond.
Cost of HPHT Lab Grown Diamonds
In the last two years, the retail synthetic diamond price has significantly decreased by up to 50%. Likewise, the wholesale natural and synthetic diamond price has also gone down threefold.
The key trends that have affected prices in the diamond industry have been outlined in the report titled “The Global Diamond Industry 2018” published by Bain AWDC.
According to the report, the decreasing prices can be attributed to the rising influence of digital technologies. The advancements that technology has made have resulted in the simplification of the process of making man-made diamonds. Ultimately, this has resulted in reduced synthetic diamond prices on the global market.
As per the report, back in 2008, the cost of producing just one carat of lab grown diamonds was roughly $4000. However, with the technological advancements made in the previous decade, the lab grown diamond price has drastically dropped down to roughly $300 to $500 per carat.
Other factors that have affected the price of diamonds also include the buying habits of the younger generation as well as the growing presence of man-made diamonds in the global market. The younger generation today prefers to go for high quality and uniqueness.
The declining production cost and a wider buying audience are bound to increase the demand for both natural and lab grown diamonds. The report also predicts that with the increase in production efficiency and the introduction of new competitors in the market, along with the commoditization of the industry, natural and synthetic diamond prices are expected to fall further.
Uses of Lab Grown Diamonds
Credited by their durability, increasing affordability and availability, lab grown diamonds are now being used in several industrial applications. These include:
Machining Tools
Hardness is an attribute that’s essential for all cutting and machining tools. Diamonds are known for their hardness, which is why man-made diamonds are being widely used in the production of machining tools for industry use as well as hardware. Since diamonds can be used for polishing, cutting, and wearing away any material, common industrial applications include diamond-tipped drill bits and saws. Diamond powder can also be used as an abrasive as well as wear-resistant coating on bearings and tools.
Thermal Conductor
Pure lab grown diamonds are characterized by their negligible electrical conductivity and high thermal conductivity. Both of these qualities make it perfect to use as a heat sink for high power transistors, laser arrays, and high power laser diodes. In semiconductors, man-made diamonds are used as heat spreaders to prevent semiconducting devices and silicon from overheating.
Optical Materials
As mentioned earlier, a diamond is hard. Along with that, it has high thermal conductivity, is chemically inert, and possesses a low thermal expansion coefficient. Due to these properties, lab grown diamonds emerge as superior to other window materials used for transmitting microwave and infrared radiation. For this reason, lab grown diamonds are being used instead of zinc selenide as output windows of high-power CO2 lasers as well as gyrotrons.
In addition, lab grown diamonds can also be used for creating designer optically-transparent diamond anvils. These anvils can then be used for measuring the magnetic and electric properties of materials at high-pressure with the help of diamond anvil cells.
Electronics
Today, synthetic diamonds for sale are used for making several electronic devices, which include semiconductors, electrodes, and radiation detection devices.
Jewelry
Since man-made diamonds are available in a variety of colors, these are ideal for different jewelry and accessories, including necklaces and bracelets. However, perhaps the most common use of diamonds in jewelry is to make HPHT diamond rings. Plus, given the declining cost of man-made diamonds, the prices of HPHT diamond rings and necklaces are widely affordable.
Memorial Diamonds
Memorial diamonds are lab made diamonds that are used for paying eternal tribute and commemorating the memory of a deceased loved one. For this HPHT diamond process, the ashes of the deceased are used to make the lab grown diamonds.
The lab grown diamond price for these gems starts at $1250 USD
Medical Applications
Lab grown diamonds are being used in advanced healthcare applications. For instance, they are used for the therapy of eye-cancer patients. Radiation detectors based on lab grown diamonds ensure the delivery of the right dosage by targeting just the cancer-affected tissue. At the same time, it makes sure that the healthy tissues around the cancer-affected areas are not targeted. Similarly, lab grown diamonds are used as surgical scalpels in ophthalmic and neurosurgery.
HPHT Lab Grown Diamonds in Jewelry
As mentioned earlier, synthetic diamonds for sale can be used to make HPHT diamond rings. Apart from that, there are other applications of man-made diamonds in jewelry.
It’s easy to cut lab grown diamonds into classical shapes that can then be made into jewelry pieces as per the client’s choices. These jewelry pieces range from pendants, necklaces to earrings, simple bracelets and HPHT diamond rings.
In addition, lab grown diamonds are available in a plethora of different colors, including blue and yellow. Therefore, they are perfect for jewelry pieces, specifically for whole sets of necklaces and earrings fitted with different colored diamonds. In fact, it’s possible to make different styles and lengths of earrings, such as large drop-shaped earrings or small hoops.
The same is the case for rings. With the different shapes and colors, lab grown diamonds can be used for making different kinds of HPHT diamond rings, including engagement rings, wedding bands, and even promise rings.
The jewelry setting of your choice has an impact on the resulting lab grown diamond price. Not to mention, the lab grown diamond price also varies depending on the synthetic diamond vendor you will have selected.
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