A grey stone with clear flat layers, and a fish fossil pressed into one of them. What's its story?
Tap to reveal
Sedimentary
Layers and a fossil are the giveaway: this is sedimentary rock. Sediment piled up gently on a calm lake or seabed, burying the fish before it rotted. Compaction and cementation turned the layers — and the fish — to stone. Fossils only ever form here.
A speckled stone packed with big interlocking crystals, no layers at all. What's its story?
Tap to reveal
Igneous
Big interlocking crystals mean molten rock that cooled slowly, deep underground — this is igneous granite. Slow cooling gave the crystals time to grow large. It formed far below the surface and was lifted up and exposed much later.
A hard rock with wavy bands, its minerals stretched and smeared into stripes. What's its story?
Tap to reveal
Metamorphic
Banding and smeared minerals mean fierce heat and pressure without melting — this is metamorphic rock. An older rock was buried deep and squeezed so hard its minerals recrystallised into stripes. Melt it and it'd be igneous instead.
Uluru stands above a flat desert, its huge sides grooved and flaking. What's its story?
Tap to reveal
Sedimentary
Uluru is sedimentary — sand laid down, buried and cemented, then tilted nearly vertical and slowly weathered. Those grooves and flakes are weathering still at work, breaking the surface down grain by grain over a vast stretch of time.
Dark, glassy rock with crystals so tiny you can barely see them, from an old lava flow. What's its story?
Tap to reveal
Igneous
Still igneous — but the tiny crystals mean it cooled fast, as lava at the surface, with no time to grow big grains. That's basalt. Same family as granite, opposite cooling speed: crystal size reads the rate of cooling.