In the Quesnel region, Tertiary volcanic and sedimentary rocks overlie Paleozoic and Mesozoic rocks of the Cache Creek Complex and Nicola Group. These Tertiary rocks range in age from Paleocene to Pliocene but are dominated by plateau basalts of Miocene age and an underlying sedimentary succession including tuffs, conglomerate, sandstone and shale. Included in this sedimentary assemblage is a horizon of diatomaceous earth from which past production is recorded.

At the Quesnel occurrence, diatomite is mined from Lot 12194 (B. Warner, Clayburn Industries, personal communication, 1993). The diatomite is creamy white to buff with the main variable in composition being the amount of silt and ash present. Scattered thin layers of clay may occur as interbeds.

Production at this site began in the 1970s, but production statistics are available beginning in 1987.