bentonite — a valuable clay, formed by the decomposition of volcanic ash, that swells as it absorbs water: used as a filler in the building, paper, and pharmaceutical industries
hematite — a very common mineral, iron oxide, Fe 2 O 3 , occurring in steel-gray to black crystals and in red earthy masses: the principal ore of iron.
mennonite — a member of an evangelical Protestant sect, originating in Europe in the 16th century, that opposes infant baptism, practices baptism of believers only, restricts marriage to members of the denomination, opposes war and bearing arms, and is noted for simplicity of living and plain dress.
pegmatite — a coarsely crystalline granite or other high-silica rock occurring in veins or dikes.
plebiscite — a direct vote of the qualified voters of a state in regard to some important public question.
recondite — dealing with very profound, difficult, or abstruse subject matter: a recondite treatise.
