Pearlite

n.

1.

(Min.) A glassy volcanic rock of a grayish color and pearly luster, often having a spherulitic concretionary structure due to the curved cracks produced by contraction in cooling. See Illust. under Perlitic.

Noun

1.

pearlite - a lamellar mixture of cementite and ferrite formed during the cooling of austenite; a micro-constituent of steel and cast iron

cast iron, cementite, ferrite, globular pearlite, granular pearlite, iron carbide, lamellar mixture, steel