the.com/siderite
iron ore that fizzes in acid and once arrived from space, freezing fire into rock
iron heartIron carbonate, FeCO3, nearly half iron by weight
acid testBubbles slowly in warm acid, betraying its carbonate soul
banded pastBuilt ancient iron formations before Earth had oxygen
meteor cousinIron meteorites are also called siderites
sneaky weightSurprisingly heavy for its dull brown look