LEDs, photovoltaic cells, jewelry – artificial gemstones such as sapphire crystal are used in the production and development of these products. The crystals are grown in special furnaces. Chinese manufacturers use HBK load cells and amplifiers to monitor the stresses that emerge inside the crystal during this process. Sapphire crystals are the most important raw material for LEDs. China is now the international center of this industry. The crystals are grown in special furnaces at up to 2,050°C. A principal axis made from a silicon-based material is located in the center of the furnace. An S-shaped HBK load cell connected to the principal axis is attached in the upper section. As the temperature in the furnace increases, the sapphire crystal grows around this axis.