Material that is created with small slits in metal, forming diamond-shaped openings, is known as?

The description given in the question specifically refers to a material that has been created with small slits or openings that form a diamond shape. This process involves taking a solid piece of metal and mechanically expanding it through slitting and stretching, resulting in a mesh-like structure known as expanded metal.

Expanded metal is widely used due to its strength, lightweight properties, and versatility in various applications, such as security, ventilation, and decorative purposes. The diamond-shaped openings provide adequate airflow while preventing larger objects from passing through, making it ideal for use in fencing, screen applications, and walkway covers.

In contrast, the other materials listed have different characteristics. Hardware cloth is typically a wire mesh screen with smaller openings for use in fencing and sifting applications. Perforated metal consists of sheet metal that has been stamped or punched with holes, often round or square, rather than diamond-shaped. Punched metal also involves creating holes in a flat sheet, but it does not imply the expansion process that gives expanded metal its unique shape and strength.