Emily Dickinson Lexicon

PIS'O-LITE, n. [Gr. πισον, a pea, and λιθος, a stone.]

Peastone, a carbonate of lime, slightly colored by the oxyd of iron. It occurs in little globular concretions of the size of a pea or larger, which usually contain each a grain of sand as a nucleus. These concretions in union sometimes compose entire beds of secondary mountains. It is sometimes called calcarious tufa. – Dict. Nat. Hist. Cleaveland.