How Are Lab-Created Sapphires Made?

Base Materials

• Aluminum oxide is the base material used to create synthetic sapphires in a laboratory. Aluminum oxide contains the ingredients needed to create a final product that is similar in chemical makeup, hardness, appearance and strength as corundum. Corundum is the naturally occurring crystallized form of aluminum oxide that appears in nature and forms into stones like rubies and sapphires. In addition to the aluminum oxide, different chemicals are added to the mixture to create colored crystals.

Heat

• Within the crust of the Earth, the heat energy required to create gemstones is generated by factors such as the intense pressure exerted upon materials located miles beneath the surface. In a lab, that heat needs to be replicated artificially to create a crystallization effect in the aluminum oxide. In the most common method for creating sapphires, the Vemeuil process, temperatures of 2,050 degrees Celsius are required to create the crystals.

Crystallization

• Several methods of crystallization exist for creating sapphires. In the basic Verneuil method, the crystals are melted into a small container. The resultant product is called a boule and is shaped like a carrot. Other crystallization methods are used to produce sapphires closer to the right shape for specific applications. For instance, thin rods of boule are now produced to use in watch-making.

Cutting

• Once the base crystals have been created, they need to be cut, shaped and polished. The exact process required for the crystal depends entirely on what it is going to be used for. Obviously a product being used for jewelry needs to be crafted to have a visually appealing cut while a crystal bound for a technological application needs to be shaped for that specific job. Because sapphires are rated at 9 Mohs of hardness, there are very few materials that cut or shape them. Diamond-bladed saws and tools are typically used in crafting synthetic sapphires.