Hematite after Magnetite (variety martite)

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

Specimen size: 10 × 5.6 × 6.2 cm = 3.94” × 2.20” × 2.44”
Main crystal size: 3.8 × 3.2 cm = 1.50” × 1.26”