Dhulka diatomaceous waa nooc ka mid ah dhagaxa siliceous ee bayoolojiga ah, oo inta badan ka samaysan haraaga diatom-ka qadiimiga ah. Halabuurka kiimikada ayaa inta badan ah SiO2, oo ka kooban xaddi yar oo Al ah.₂O₃, Fe₂O₃, CaO, MgO, K₂O, Na₂O, P₂O₅iyo walxaha dabiiciga ah. Isticmaalka ugu weyn ee diatomite waa qalabka shaandhada, buuxinta, nuugayaasha, sidayaasha kicinta, qalabka dhismaha ee deegaanka u fiican iyo wixii la mid ah.