Although cartilage and sclerite are microscopically composed of cells with extracellular matrix material, the main difference is that the cells that form cartilage and sclerite are, themselves, different kinds of cells. The cells that form cartilage are chondrocytes and chondrogenic cells, while the cells that form hard bone can be divided into osteoblasts, osteoclasts, and osteoclasts. In addition, the base material outside the cells that make up cartilage is different from the base material outside the cells that make up hard bone. Most of the base material outside the cartilage cells is gelatinous material, fibrous material, etc., which determines that cartilage is a flexible structure, translucent or transparent in texture, milky or bluish in color, and also capable of producing vibrations. In contrast, most of the extracellular base material of the hard bone is calcium, phosphorus and other minerals, and there is also a small amount of gum, so the hard bone has a harder texture, slightly less elastic, and is off-white or white opaque in color.