The isotopic composition of volatiles in the unique Bench Crater carbonaceous chondrite impactor found in the Apollo 12 regolith

•The lunar regolith has accumulated volatiles from impacting hydrated asteroids.•The Bench Crater meteorite preserves hydrated minerals that survived lunar impact.•Bench Crater meteorite has unique mineralogical and stable isotope characteristics.•Bench Crater may represent material not found in the current meteorite collection.•Bench Crater is a critical ground truth for future lunar volatile resource missions.