Pellicle forms first, biofilm formation, mineralization, pellicle layer forms immediately, bacterial colonies form in the pellicle, colonies grow together forming a cohesive biofilm layer, MINERALIZATION centers form within 24-72 hours, centers eventually grow and unite, filamentous microorganisms provide the matrix for the deposition of minerals, pellicle may also mineralize explaining the stregth of the bond to tooth surface, mineral source for supraginigival calculus is saliva, mineral source for subgingival calculus is the gingival sulcus fluid and inflammatory exudate