You’ll often hear "magma" and "lava" used interchangeably. They’re almost the same thing. Magma is underground. Lava is above ground. So lava rock = extrusive igneous rock. Magma rock = intrusive igneous rock. The difference is all about location, location, location.
Intrusive rocks cool slowly deep underground. They form big, chunky crystals you can see with your naked eye. Granite is the classic example. It’s the granite countertop in your kitchen—except it was once a blistering blob of magma. Now it’s just fancy and expensive.
Funny Details to Drop at Parties
Did you know that pumice is so lightweight it can float across oceans? There’s a giant patch of floating pumice in the Pacific Ocean right now. It’s called a "pumice raft." It looks like a rock sponge that escaped a bath. Scientists think these rafts help spread marine life between islands.
The Life of Volcanic Rocks During and After an Eruption · Frontiers for
Also, basalt covers more than 70% of Earth’s surface. The ocean floor is basically a giant slab of it. So next time you’re swimming in the sea, remember you’re floating above a massive lava rock. It’s like lying on a giant, dark, supine tortoise.
And obsidian has a secret: it can be red, green, or even rainbow. That’s because of tiny iron or gas bubbles. "Rainbow obsidian" looks like a disco ball made by a volcano. It’s the Instagram influencer of the rock world.
