Both "black pearl" and "space iron" are high-end materials, and the prices are relatively expensive, but "black pearl" is more expensive. Usually refers to a rare natural gem, which is composed of substances secreted by the inner and outer layers of pearl oyster. It is dark in color and its surface is ivory black or dark green. It is mainly used in jewelry, jewelry and other fields.

Space iron, on the other hand, is a special metal extracted from meteorites, which has extremely high hardness and corrosion resistance and is generally used to manufacture high-strength and high-temperature mechanical equipment and tools.