Peña Blanca Spring is a historic witnessed Aubrite fall from Brewster County, Texas, USA, which occurred on 2 August 1946 near Marathon. After sonic booms and a distinct flight noise were heard, the meteorite fell into a small natural pond at Gage Ranch, where fragments were recovered from the water. With a total recovered mass of around 70 kg, Peña Blanca Spring is one of the most important Aubrite falls and a classic American witnessed meteorite.

Peña Blanca Spring is classified as an Aubrite, a rare type of Enstatite Achondrite formed under highly reduced, oxygen-poor conditions. Specimens are typically pale to light grey and can show a brecciated texture, reflecting impact processing on the parent body before arrival on Earth. As with other Aubrites, its mineralogy is dominated by Enstatite-rich material, giving it a distinctive character compared with darker Chondrites and many other Achondrites.

Studying Peña Blanca Spring provides valuable insight into highly reduced parent bodies, Aubrite formation, and the behaviour of fragile Achondrite material during atmospheric entry. Its witnessed fall status, unusual recovery from water, substantial recovered mass, and American provenance make it especially desirable for collectors of historic falls and rare Achondrites. Each specimen represents ancient igneous material from an unusual parent body, connected to one of the most memorable meteorite recoveries in the United States.