Density-Dependent Colour Scanning Electron Micrograph SEM (DDC-SEM) of cardiovascular<unk> , showing in orange calcium phosphate spherical particles (denser material) and, in green, the extracellular matrix (less dense material).<unk>  is the accumulation of calcium salts in a body tissue. It normally occurs in the formation of bone, but calcium can be deposited abnormally in soft tissue, causing it to harden.<unk> s may be classified on whether there is mineral balance or not, and the location of the<unk> .<unk>  may also refer to the processes of normal mineral deposition in biological systems, such as the formation of stromatolites or mollusc shells (see Biomineralization).
Calcification
Bone decalcification
Ossification
Pica 
Microcalcification
Lattice degeneration
Demineralization 
Sclerosis 