Naturally weathered olivine from metamorphosed, tectonized metadunite is corroded by funnel-shaped etch pits. Large etch pits form by weathering, and are not inherited from pre-weathering alteration of these rocks. Comparison of etch pits on olivine in naturally weathered metadunite with naturally weathered olivine phenocrysts from volcanic rocks suggests that olivine etch pits are similar in all sample suites, despite differences in crystallization and weathering/exposure ages, and regolith history.