Spongolite is a stone

Rock (geology)

In geology, rock or stone is a naturally occurring solid aggregate of minerals and/or mineraloids.The Earth's outer solid layer, the lithosphere, is made of rock. In general rocks are of three types, namely, igneous, sedimentary, and metamorphic...

 made almost entirely from fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

ised sponge

Sea sponge

Sponges are animals of the phylum Porifera . Their bodies consist of jelly-like mesohyl sandwiched between two thin layers of cells. While all animals have unspecialized cells that can transform into specialized cells, sponges are unique in having some specialized cells, but can also have...

s. It is light and porous.

The silica spicules fossilised with the sponges makes the material hazardous to handle by being highly abrasive. Because the spicules are embedded in soft fossils, the abrasion damage is not as immediately apparent as it would be from sandpaper or rough bricks.

Spongolite is obtained from mines in Mount Barker, Western Australia

Mount Barker, Western Australia

Mount Barker is a town on the Albany Highway and is the administrative centre of the Shire of Plantagenet in the Great Southern region of Western Australia...

 and Mato Grosso do Sul

Mato Grosso do Sul

Mato Grosso do Sul is one of the states of Brazil.Neighboring Brazilian states are Mato Grosso, Goiás, Minas Gerais, São Paulo and Paraná. It also borders the countries of Paraguay and Bolivia to the west. The economy of the state is largely based on agriculture and cattle-raising...

, Brazil

Brazil

Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...

. There are also large deposits near Esperance, Western Australia

Esperance, Western Australia

Esperance is a large town in the Goldfields-Esperance region of Western Australia, located on the Southern Ocean coastline approximately east-southeast of the state capital, Perth. The shire of Esperance is home to 9,536 people as of the 2006 census, its major industries are tourism, agriculture,...

.