How lab-grown gemstones are created
The science behind growing diamonds, sapphires, emeralds, and rubies in a laboratory — and why the results are identical to mined stones.
Growing diamonds
Two methods dominate diamond creation in laboratories, each replicating different aspects of how diamonds form naturally in the earth.
HPHT method
High Pressure, High Temperature recreates conditions found 100 miles underground. A diamond seed is placed in pure carbon, then subjected to temperatures above 1,400°C and pressures of 60,000 atmospheres. The carbon melts and crystallizes around the seed over several days.
CVD method
Chemical Vapor Deposition places a diamond seed in a chamber heated to 800°C, filled with carbon-rich gas. The gas ionizes, and pure carbon atoms deposit layer by layer onto the seed, building the diamond over several weeks. This method allows precise control of the diamond’s properties.
Growing sapphires and rubies
Sapphires and rubies are both varieties of corundum (aluminum oxide). Every sapphire and ruby in a Mercury & Sol piece is grown by the Czochralski method, where aluminum oxide powder is melted at over 2,000°C and a crystal seed is slowly drawn from the melt, pulling a perfect crystal behind it. Trace elements are added to produce specific colors — chromium for pink and red, iron and titanium for blue, iron alone for yellow.
Growing emeralds
Emeralds (beryl) are grown hydrothermally, simulating the water-rich environments where natural emeralds form. A nutrient solution containing beryllium, aluminum, and silicon is sealed in a high-pressure vessel with chromium and vanadium for the green color. Over weeks, emerald crystals grow on seed plates inside the vessel.
Growing alexandrite
Lab-grown alexandrite is created using the Czochralski method with carefully controlled amounts of chromium. The resulting crystals display the same remarkable color-change phenomenon as natural alexandrite — appearing teal-green in daylight and reddish-purple under incandescent light.
Every method produces stones with the same crystal structure, hardness, optical properties, and chemical composition as their mined counterparts. The laboratory simply provides the conditions — nature provides the chemistry.
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