Lab grown gem material is one that is made in a laboratory, but which shares virtually all chemical, optical, and physical characteristics of its natural mineral counterpart.
Lab grown gem crystals have been manufactured since the late 1800s, and their production is often marked by a need for them in industrial applications outside of the jewellery industry, (e.g. communications and laser technology, microelectronics, and abrasives). Because lab grown stones have a consistent colour and crystal shape, given the right ingredients, time, and the facilities to grow them, they are likely to be much less rare than natural gems of equal size, clarity, and saturation of colour. Because of this, and because it is possible to confuse them with gems that are naturally occurring, there are strict guidelines regarding how they are marketed and sold.
During the last century, researchers have developed a number of different ways to create these lab grown gem materials in the laboratory.
The first commercially successful lab grown gems were created by the flame fusion process. This process involves dropping powdered chemicals through a high-temperature flame, where it melts and falls onto a rotating pedestal to produce a crystal. Today it remains the most common way to create gems such as corundum and spinel.
Pulling emerged in the early 1900s. In this process, nutrients are melted in a crucible and the crystal grows from a corundum seed that is dipped into the melt, and then slowly pulled away from the melt as it grows. Gems created by pulling include lab grown alexandrite, chrysoberyl, corundum, and garnet.
Today some lab grown gems, such as emerald, ruby, sapphire, alexandrite, and spinel can be created through a flux-growth process. Flux is a solid material that, when melted, dissolves other materials in the same way that water dissolves sugar. As the dissolved chemical solution gradually cools, crystals form.
Growing a gemstone by the flux method requires patience and significant investment. Crystal growth can take up to a year. But the results, especially when it comes to emerald, are well worth the time and effort.
Like the flux process, the hydrothermal growth process is slow. But it’s the only method for successfully growing quartz. This process requires heat and pressure and imitates the conditions deep in the earth that result in the formation of natural gems. Nutrients are dissolved in a water solution, and then crystals form as the solution cools.