Diatomite（kieselguhr 、kieselgur 、tripoli 、infusorlal earth） is a kind of sediment rock of silicon character with biology cause of formation, mainly consisting of remains of ancient diatom, taking SiO2 as main chemical compositions, opal and its variation as mineral compositions. SiO2 in diatomite（kieselguhr 、kieselgur 、 tripoli 、infusorlal earth） is different from that in other minerals and rocks on structure and compositions, and it is an amorphous opal mineral with organic cause of formation, generally called diatomaceous silicon dioxide. Beside H2O and SiO2, there is a small quantity of Fe, Al, Ca, Mg, K, Na and other impurities in diatomite. As per crude ore quality, the diatomite（kieselguhr 、 kieselgur 、tripoli 、infusorlal earth） could be divided into diatomite, clay-inclusive diatomite and clay diatomite. Diatomite （kieselguhr 、 kieselgur 、 tripoli 、infusorlal earth）refers to the content of diatom shell accounting for above 80% in crude ore, while clay-inclusive diatomite contains more than 70% of diatom shell in crude ore, and clay diatomite contains about 60% of diatom shell in crude ore, showing that the last one is of bad quality.
