Scoria
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Mineral NameScoria
Chemical FormulaVariable (mafic silicates, rich in Fe, Mg, Ca, Al)
Streak ColorGray to brownish-black
CleavageNone (rock); constituent minerals may have cleavage
FractureUneven to conchoidal (for individual fragments)
Specific Gravity1
Colorsdark brown, black, reddish-brown
TransparencyOpaque
Type LocalityVolcanic regions worldwide (e.g., Hawaii, Iceland, Italy)
Mineral GroupIgneous rock (mafic volcanic rock)
Useslandscaping, barbecue briquettes, lightweight aggregate, drainage material
Associated Mineralsolivine, pyroxene, plagioclase feldspar
Raritycommon
Description
A dark, highly vesicular igneous rock characterized by numerous gas bubbles (vesicles), giving it a sponge-like or frothy texture. Its color typically ranges from dark brown to black or reddish-brown.
Geological Context
Scoria forms during explosive volcanic eruptions when mafic lava cools rapidly, trapping gas bubbles as it solidifies. It is a common product of basaltic volcanism, often found in cinder cones and lava flows.
