NASA's Curiosity Mars rover spotted this chunky iron-nickel meteorite on the Red Planet's Mount Sharp. Nicknamed "Cacao," it's estimated to be one foot across. From Science Alert:
Iron-nickel meteorites are the rarest type of meteorites, making up about six percent of witnessed falls. But because of their tell-tale visual appearance, they're over-represented in collections. That's because they're more likely to survive passage through an atmosphere and are more resistant to weathering, even on Mars.
Most iron-nickel meteorites come from the cores of shattered planetesimals that formed in the early Solar System. Those objects were large enough to differentiate when they were molten. They formed a core of dense iron and nickel, much like Earth did.
But life as a planetesimal was risky, and many of them were shattered into asteroids. That's Cacao's likely history.
More info at NASA's Jet Propulsion Lab.