Hematite after Magnetite (variety martite)

Payún Matru Volcano, Malargüe, Malargüe Department, Mendoza Province  Argentina (2008)

Specimen size: 7.7 × 7.5 × 5.9 cm = 3.03” × 2.95” × 2.32”
Main crystal size: 5.2 × 2 cm = 2.05” × 0.79”