A special funnel that is used for filtering solid matter out of a solution. Half-way down the funnel is a flat disk of glass with millions of microscopic holes (pores) in it. The liquid passes through the disk, but any solid matter is trapped on the glass disk. This disk is made of glass that has been sintered. It is called a crucible because it can be heated in an oven to high temperatures so that the solid matter trapped on the filter can be dried.

A chemist uses a sintered glass crucible, and not filter paper, whenever the solid matter must be dried in an oven, as filter paper will burn in an oven.