Martian spherules (also known as hematite spherules, blueberries, & Martian blueberries) are small spherules (roughly spherical pebbles) that are rich in an iron oxide (grey hematite, α‐Fe2O3) and are found at Meridiani Planum (a large plain on Mars) in mind-bogglingly large numbers. * Loose hematite spherules at Eagle Crater. Spherule diameters are 3-6 mm. * Close-up of sediment matrix with embedded hematite spherules at Eagle Crater. The central (partially embedded) spherule is 3.7 mm in diameter. * Small, loose hematite spherules northwest of Victoria Crater. Spherule diameters are 1 - 2 mm.