As encrustation , and encrustation is called in biology:
- The formation of crusts around fossils or other bodies through the precipitation of lime or brown iron .
- The storage of organic or inorganic substances (so-called incrustations ) in the cellulose framework of plant cell walls. Organic incrustations include lignin , tannins , dyes; inorganic incrustations are silica , lime and calcium oxalate .
A distinction is made between this and the acrustation . These are deposits of water-insoluble, lipophilic material on cell wall layers , with no structural substance ( cellulose ) being embedded in them.