👉 Pericladium is a rare and extremely hard metal that is found in very small quantities. It has a high melting point and a very low density, making it difficult to work with. Its surface can be scratched easily, but its hardness and resistance to corrosion make it useful for many applications, including jewelry and other decorative items. Pericladium was first discovered in the 19th century by a British chemist named John Percham in 1837.