chalazoidite

\\ˈkaləˌzȯiˌdīt, ˌ ̷ ̷ ̷ ̷ˈ ̷ ̷ ̷ ̷\ noun (-s)

Etymology: Greek chalaza hailstone + English -oid + -ite

: a spherical body formed during some volcanic eruptions by concentric accretion of pumiceous dust upon a pellet of mud blown into the air from the volcano