Spongolite

Spongolite (also spelled spongilite, spongillite, or spongiolite) is a sediment or sedimentary rock composed principally of the remains of largely articulated fossils of rigid-bodied siliceous sponges. In contrast, spiculite is either sediment or sedimentary rock composed of mostly disarticulated, discrete siliceous sponge spicules. As seen below, in some older papers, spongolite is used as a synonym of spiculite.

In Brazil, the term spongolite is defined differently as a nonmarine, freshwater, lacustrine sediment "..essentially composed of siliceous sponge spicules of the Demospongiae Class, associated with clay, sand, organic matter and diatom residues." In this usage of the term spongolite, the term spiculite is restricted to marine sediments composed of siliceous sponge spicules.