An osteoblast (from the Greek words for "bone" and "to build") is a cell which produces osteoid.

Osteoid is a protein mixture which is secreted by osteoblasts. When it mineralizes, it becomes bone. Osteoid is primarily composed of type 1 collagen.

Source: Research Report: National Center for Complementary and Alternative Medicine (NCCAM):

“There are some uses of electromagnets within conventional medicine. For example, scientists have found that electromagnets can be used to speed the healing of bone fractures that are not healing well” (NCCAM 3).