Osteoblast bone cell surrounded by osteoid (cream), coloured scanning electron micrograph (SEM). Osteoblasts are primarily found in regions of new bone growth. They produce and secrete the osteoid, the matrix of the new bone composed of collagen fibrils and other structural proteins. As soon as osteoid is formed, calcium salts crystallise inside it to form hard, mineralised bone. Magnification: x6760 when printed 10 centimetres wide.