How are laboratory-grown stones created?
The 20th century was the century of great scientific advances in gemmology, the science of studying precious, semi-precious and fine stones, was no exception to this trend. Although important discoveries had been made earlier on the atomic structure of crystals, it was during this century that countless researchers began to study the chemical properties of diamonds, rubies, sapphires, emeralds and other precious stones. They joined forces with physicists to reproduce what the planet has naturally created over millions of years.
Defining a lab-grown stone.
In gemology, a gem is said to be synthetic when it is manufactured by human hands while having the same chemical composition, atomic structure and visual appearance as its natural counterpart. Its microstructure must also cause the same optical effects.
The first synthetic diamonds
Laboratory diamonds were first used for all kinds of industrial applications. Over time, manufacturing techniques have been refined and production costs have decreased. Synthetic diamonds became more beautiful and less expensive. They began to intrigue jewellers in the mid-1990s. However, it would be another 25 years before the buyer would become interested.
Buying a lab-grown diamond
You may have come across this text while searching for where to buy your synthetic diamond. The question is a good one and the fear is certainly legitimate, but rest assured, there are no fake diamonds created in a laboratory. Natural diamonds and laboratory-created diamonds must meet the same requirements to be sold on the market. Machine-made diamonds are even potentially purer than mined diamonds, which are often contaminated with mineral inclusions. Any trusted jeweller with a concern for the environment offers engagement rings with lab-grown diamonds. In jewellery, the market share of laboratory-made diamonds is steadily increasing and the trend has been accelerating since 2018. Less expensive, more ethical, these stones will represent between 3 and 4% of the global diamond market by 2021.
Solitaire with synthetic diamond
Creating diamonds in the laboratory
Lab grown diamonds
It is in 1954 that one officially recognizes the creation of the first synthetic diamond by Tracy Hall of the General Electric company. Today, there are two techniques for creating these cultured diamonds, called synthetic diamonds: the HPHT method (High Pressure High Temperature) and the VCD technique (Chemical Vapour Deposition). The first, HPHT, reproduces, in a machine, the conditions undergone by a carbon compound 150 km underground, i.e. a pressure of 60,000 times our atmosphere and a temperature of around 1400°C. The second, DCV, consists of placing a diamond seed in a chamber where a flow of methane or another carbon-rich gas is injected and dissociated into atoms by a microwave discharge. At high temperatures, the gas turns into plasma and, miraculously, the carbon crystallises. This crystalline form of carbon is then deposited on this seed and the diamond grows. Unlike HPHT, this process requires no atmospheric pressure and produces a diamond of high quality and purity.
What about other lab-grown stones?
Many gemstones can be reproduced and the methods vary from stone to stone. Let's focus on the technique that creates coloured stones,such as rubies, sapphires and emeralds. All of these gemstone manufacturing processes have seen great improvements since their inception.
Flame fusion growth
This synthesis was officially unveiled in 1902 by the French chemist Auguste Victor Louis Verneuil. It allows the creation of synthetic rubies and sapphires of the Verneuil type by melting alumina at temperatures of over 2500°C. The crystal deposit is formed drop by drop, by superimposing very thin layers of molten material.
Growth by anhydrous dissolution
Created in 1847 by the French chemist Jacques Joseph Ebelmen, this technique combines in a platinum crucible the components of the desired synthetic gem, an important mineral called silica, a chemical colouring agent and an anhydrous flux (without water). The whole is heated under ambient pressure to the temperature of dissolution and recrystallisation into single crystals. A slow rotation allows the recovery of rubies, sapphires and emeralds.
Growth by hydrothermal dissolution
The first attempts at this process were made by the 19th century German geologist Karl Emil von Schafhaüt. Crystal growth occurs in a sort of pressure cooker combining heat and pressure with water as a solvent. The chemical constituents of the stone are dissolved, heated to high temperatures and put under high pressure. They crystallise around an existing gem, usually an emerald.
Synthetic emeralds, ruby and sapphire
Buying synthetic gemstones
Just like the synthetic diamond the price of a synthetic ruby or a synthetic sapphire is about 30 to 40% less expensive. This reality is shaking up the gemstone market, much to the chagrin of traditional producers. Add to this the growing concern of new generations about the traceability of these gems. According to the NGO Human Rights Watch the trade in diamonds and gems continues to be associated with serious human rights abuses, including forced labour. And how can we ignore the impact on the environment through soil erosion, deforestation and the disappearance of wildlife?
Diamond mine
Are you ready for synthetic gems?
At Flamme en rose, we are committed to designing jewellery that respects environmental protection and sustainable development standards by avoiding the use of non-renewable resources and by promoting the reuse and recycling of materials. This is what we call eco-design. So we naturally turned to laboratory-created gemstones. And so have our customers. And you, are you ready to buy a piece of jewellery handmade with laboratory-created gems?
Get an online consultation with one of our jewellers today.
