In intramembranous ossification, newly formed bone that is immature and not well organized is called woven bone. Osteoblasts are the type of cells that is responsible for the formation of new bone. These osteoblasts also come from the bone marrow and are related to structural cells. They have only one nucleus. The process of bone formation is called osteogenesis whereas there are three stages of bone development i.e. proliferation, maturation of matrix, and mineralization.