Hematite after Magnetite (variety martite)

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

Specimen size: 7.4 × 6.3 × 4.7 cm = 2.9” × 2.5” × 1.9”
Main crystal size: 3.5 × 2.5 cm = 1.4” × 1.0”