What characteristic defines the nature of diamonds in industrial applications?

In industrial applications, diamonds are primarily valued for their physical properties rather than their aesthetic qualities. The defining characteristic for the use of diamonds in industrial settings is their hardness. Diamonds are the hardest known natural material, making them ideal for cutting, grinding, drilling, and polishing.

The term "low quality" in this context refers to industrial diamonds, which do not need the clarity, color, or brilliance that are desirable in gemstones. These diamonds are often opaque or have inclusions, making them unsuitable for jewelry but perfect for industrial use. Consequently, while these diamonds may not possess the rare and unique attributes that are valued in gem-quality diamonds, their industrial application relies heavily on their physical toughness rather than visual appeal.