Scoria vs. Pumice — What's the Difference?

Typically found near volcanoes.

Used as an abrasive material.

Formed from magma with high iron and magnesium.

Forms during explosive volcanic eruptions.

A dark volcanic rock with vesicles.

A light, porous volcanic glass.

Heavier and denser volcanic rock.

Can float on water due to high porosity.

Used in heavy-duty construction.

Highly vesicular structure.

Scoria is a highly vesicular, dark-colored volcanic rock that may or may not contain crystals (phenocrysts). It is typically dark in color (generally dark brown, black or purplish red), and basaltic or andesitic in composition.

Pumice ( ), called pumicite in its powdered or dust form, is a volcanic rock that consists of highly vesicular rough textured volcanic glass, which may or may not contain crystals. It is typically light colored.

(Geology) Porous cinderlike fragments of dark lava. Also called cinders, slag.

A light, porous, glassy lava, used in solid form as an abrasive and in powdered form as a polish and an abrasive.

(Metallurgy) The refuse of a smelted metal or ore; slag. Also called cinder.

To clean, polish, or smooth with pumice.

The slag or dross that remains after the smelting of metal from an ore.

A light, porous type of pyroclastic igneous rock, formed during explosive volcanic eruptions when liquid lava is ejected into water or air as a froth containing masses of gas bubbles, which are frozen into the rock as the lava solidifies.

(geology) Rough masses of rock formed by solidified lava, and which can be found around a volcano's crater.

(transitive) To abrade or roughen with pumice.

The recrement of metals in fusion, or the slag rejected after the reduction of metallic ores; dross.

A very light porous volcanic scoria, usually of a gray color, the pores of which are capillary and parallel, giving it a fibrous structure. It is supposed to be produced by the disengagement of watery vapor without liquid or plastic lava. It is much used, esp. in the form of powder, for smoothing and polishing. Called also pumice stone.

Cellular slaggy lava; volcanic cinders.

A light glass formed on the surface of some lavas; used as an abrasive

The scum formed by oxidation at the surface of molten metals

Scoria is typically used for landscaping, drainage solutions, and as aggregate in lightweight concrete.

Pumice floats on water due to its extremely porous structure, which traps enough air to keep it buoyant.

The dark color of scoria is due to its high iron and magnesium content, which oxidize upon exposure to air.

Scoria and pumice can be found in volcanic regions around the world, although their presence and abundance may vary.

Pumice is used in beauty products for its abrasive properties, effective in removing dead skin and polishing surfaces.

Yes, the size and distribution of vesicles can indicate the speed of cooling and the volatility of the eruption, with more explosive eruptions producing finer, more interconnected vesicles as seen in pumice.

Mining scoria and pumice can disrupt local ecosystems, although impacts vary depending on the scale and method of extraction.

Yes, scoria's porous nature and durability make it suitable for use in water filtration systems.

When using pumice, particularly as an abrasive, it is important to handle it gently to avoid excessive abrasion and skin damage.

Both scoria and pumice are mined from volcanic deposits, often using quarrying methods.