Collection of volcanic scoria
Italy, private collection from Sweden.
Scoria is a pyroclastic, highly vesicular, dark-colored volcanic rock that was ejected from a volcano as a molten blob and cooled in the air to form discrete grains or clasts. It is typically dark in color (generally dark brown, black or purplish-red), and basaltic orandesitic in composition. Scoria is relatively low in density as a result of its numerous macroscopic ellipsoidal vesicles, but in contrast to pumice, all scoria has a specific gravity greater than 1, and sinks in water. The word scoria comes from the Greek skōria, (σκωρία) rust.
Lovely small collection (4) of volcanic rocks. Good condition. Age-related wear, fractures and minor cracks may appear. Dirt and dust may exist. Size varies from approx. 7,2cm to 2,5cm. Total weight c. 356g.