lithophagous

Century Dictionary and Cyclopedia

1. Eating stones; swallowing gravel, as a bird.
2. Perforating or penetrating stones, as the Lithophaga; lithodomous.

Wiktionary

1. adj. zoology Eating or swallowing stones or gravel.
2. adj. zoology Eating or destroying stone, like some mollusks, sponges, annelids, and sea urchins.

GNU Webster's 1913

1. adj. Eating or swallowing stones or gravel, as the ostrich.
2. adj. Eating or destroying stone; -- applied to various animals which make burrows in stone, as many bivalve mollusks, certain sponges, annelids, and sea urchins. See lithodomus.