Hematite after Magnetite (variety martite)

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

Specimen size: 10.1 × 6.2 × 5.6 cm = 3.98” × 2.44” × 2.20”
Main crystal size: 6 × 3.4 cm = 2.36” × 1.34”