<prompt> The bone matrix has the following crystalsCalcium hydroxyapatiteCalcium pyrophosphateCalcium phosphateCalcium sulphate  <response>: The bone is made up of bone cells and extracellular matrix.The matrix consists oftwo types of materials,organic and inorganic. The organic matrix is formed by the collagen,which forms 30-35 of dry weight of a bone. The inorganic matrix is primarily calcium and phophorus salts,especially hydroxyapatite .It constitutes about 65-70 of dry weight of a bone. ref:maheswari,5th edition page no.9 