Hematite after Magnetite (variety martite)

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

Specimen size: 5.3 × 3.3 × 2.2 cm = 2.09” × 1.30” × 0.87”
Main crystal size: 3.5 × 1.5 cm = 1.38” × 0.59”