Which process is often employed to grow synthetic gemstones in large volumes?

Flame fusion is a widely used process for growing synthetic gemstones in large quantities. This method involves melting raw materials together in a high-temperature flame, which allows for rapid production of synthetic crystals. The molten material falls from the flame and cools, forming crystals as it solidifies. Flame fusion not only enables the creation of gemstones at a much lower cost compared to natural stones, but it also allows for the control of the color and clarity of the resulting gems, making it a popular choice in the industry.

In contrast, other methods like hydrothermal growth are more suitable for producing large crystals but are time-consuming and typically lead to smaller-scale production compared to flame fusion. Gas deposition and seed growth are also effective for specific types of materials or applications, but they do not match the efficiency and volume capabilities of flame fusion in terms of producing synthetic gemstones.