What are Laboratory Grown or LAB Diamonds ?
HPHT Method for Growing Laboratory Grown Diamonds
The High Pressure High Temperature (HPHT) method to produce synthetic diamonds uses large presses that can weigh several hundred tons and enormous heat to reproduce the conditions that created natural diamonds. Diamond growth occurs when a form of carbon, graphite, is subjected to this high heat and diamond stabilising pressures in the presence of a metal for a certain period of time. The metal acts as a solvent for the graphite, and also acts as a catalyst to enable crystal growth.
To create coloured HPHT synthetic diamonds, the as-grown diamond crystal may be treated with various methods to induce a colour change, just as natural diamonds are colour treated.
CVD Method for Growing Laboratory Grown Diamonds
The second method, using Chemical Vapour Deposition or CVD, is very much like the process of creating frost on a window pane, when water molecules condense from the air and create a layer of frost. Diamond crystals are formed from a carbon-containing gas without the use of pressure.
The CVD method for growing synthetic diamonds was invented in the 1980s, and involves mixing gases (typically methane and hydrogen) in a vacuum chamber. When heat is applied inside the chamber, chemical reactions of the gas mixture deposit synthetic diamond onto a diamond substrate.
All Natural diamonds will have a notation of Natural Diamond on the report, and all Laboratory grown diamonds must state Laboratory Grown Diamonds.
The main difference between a natural mined diamond and a laboratory grown diamond is their origin. Natural diamonds are formed deep within the Earth’s mantle under extreme heat and pressure over millions of years, while laboratory grown diamonds are created in a controlled environment in a laboratory setting.
Some other differences between natural mined diamonds and laboratory grown diamonds include:
- Cost: Laboratory grown diamonds are generally less expensive than natural mined diamonds, as they don’t require expensive mining and extraction processes.
- Clarity: Laboratory grown diamonds are generally more consistent in terms of their clarity, as they are grown under controlled conditions. Natural mined diamonds can have inclusions or blemishes, which can affect their clarity and value.
- Size and Colour: Laboratory grown diamonds can be grown to larger sizes and in a wider range of colours, which may not be as easily available in natural mined diamonds.
- Environmental impact: The environmental impact of laboratory grown diamonds is generally considered to be lower than that of natural mined diamonds, as mining can have a significant impact on the environment.
- Rarity and Value: Natural mined diamonds are still considered more rare and valuable than laboratory grown diamonds, due to their long history and cultural significance.
Ultimately, whether someone chooses a natural mined diamond or a laboratory grown diamond may depend on their personal preferences and priorities, such as environmental concerns, budget, or the desire for a natural, unique stone.
It is worth noting that both natural mined diamonds and laboratory grown diamonds are chemically and physically identical, and both can be certified and graded by independent gemmological laboratories based on the same criteria.
Laboratory Grown diamond can be optically and chemically identical to natural diamond.
Gem-quality synthetic diamonds are predominantly cubic and octahedral in the rough form. Impurities were common, but as the technology has progressed so the rough diamond crystals have improved. A diamond’s hardness can vary depending on its impurities and crystalline structure.
Although Laboratory Grown diamonds have similar structure and chemical properties to a natural diamond, they can be conclusively identified by differences in atomic structure and trace impurities due to their different growth environment.
Colour zoning, inclusions, fluorescence and other properties of synthetic diamonds provide practical visual indicators using standard gemological techniques and equipment, but conclusive identification requires advanced equipment and trained technicians in a laboratory.
DCLA does certify synthetic diamonds, and all laboratories that do opt to certify synthetic diamonds must clearly state on the certificate that the diamond is a laboratory-created, synthetic diamond.
There are currently two known processes for growing synthetic gem-quality diamonds: the High Pressure High Temperature (HPHT) method, and the Chemical Vapour Deposition (CVD) method.