Rocks vs. Minerals

Rockling — Rocks vs. Minerals Lantern Gate Basecamp | The Shimmering Caverns No spoken narration. Dialogue appears in speech bubbles.

Oh, good! You found Lantern Gate. I'm Rockling. And I could use your help.

I pass this arch every day. See my specimen shelf? The Grumblies mixed up every label! Hmm. We'll sort it out. One clue at a time.

Bring those clues into the lantern light. Here's what I know. Rocks and minerals are connected... ...but they're not the same thing.

A mineral forms naturally. It's a solid, and it's inorganic. It isn't material made from the remains of living things, like wood. Quartz is a mineral.

Each mineral has a particular chemical recipe. Scientists call that its composition. That's a big clue! We're asking what it's made of... ...not just what color it looks.

There's another clue inside. A mineral's tiny building pieces are called atoms. They repeat in an orderly pattern. That's its crystal structure. You can't see atoms with your eyes. These dots are just a model.

Look at those quartz points! Neat, aren't they? But a mineral doesn't need a perfect pointed shape. Break off a piece of quartz, and it's still quartz. Same chemical recipe. Same internal structure.

Now, a rock is naturally formed solid material. Most rocks contain pieces or crystals of one or more minerals. Those little parts are often called grains. One mineral kind... or several together.

Here's granite. It's a rock that commonly contains quartz, feldspar, and mica. Those are minerals! See how our model puts different grains together? Minerals are like ingredients. Granite is the rock they form.

A piece of quartz can be a specimen we study by itself. Or quartz can be one grain inside a rock. Same mineral, different place. Now our labels are starting to make sense.

Will you help me label these? Quartz on the left. Granite on the right. Which is the mineral? Take a good look.

Quartz! Granite gets the rock label. If you chose differently, take another look at the ingredients. You've got this.

This is my specimen bond: River Rock. Moving water can tumble rock fragments... ...and wear their edges smooth. But river rock isn't one mineral's name. Two smooth river pebbles can contain different minerals.

Hmm. A smooth, gray pebble. Is that enough to call it quartz? No. Smooth describes its surface. It doesn't tell us the ingredients. I look for grains and patterns, then use more clues.

Scientists compare several properties to identify minerals. Color alone can fool us. Shine alone can, too. And size? A tiny rock is still a rock! We need evidence, not just a quick guess.

One more clue. Not every rock has several mineral kinds. Some contain mainly one mineral. Obsidian is a rock made of natural volcanic glass. That glass lacks a mineral's repeating internal order.

Let's gather three clues. Minerals: a chemical recipe and repeating structure. Rocks: commonly one or more minerals together. River rock: worn smooth by water... ...but not one particular mineral.

There. Back at my shelf. Thanks, adventurer! Lantern Gate still needs us. Choose Train More for free practice. Or Start Adventure to help me. Back to Map opens all six settings. I'll be right here.

Free Rocks vs. Minerals teacher guide and practice (PDF)