Have you ever heard someone call a diamond a rock?

Icon of blue diamond gem from the side with yellow sparkles.

When someone gets engaged to be married, a friend might say, "Let me see that rock!" and want to see their new diamond ring.

A blonde woman in a white floral dress walks into a room holding up her hand with an engagement ring on it.

But is a diamond actually a rock? Or is it something else?

To find the answer, you need to understand what a rock is and how it’s different than a mineral. Then you’ll see how a diamond fits in.

Olmec, the large stone head from Legends from the Hidden Temple, saying

What is a Rock?

A rock is a solid mixture of different things like minerals, pieces of other rocks, or dead plant or animal remains.

Rocks are divided into 3 groups based on how they form:

  • Igneous rocks are cooled and hardened molten magma from inside the Earth.

Magma flowing towards the camera and spurting into the air in the distance, in front of a mountain. Photo by Jonatan Pie on Unsplash
  • Sedimentary rocks have many layers of rock and dead plants or animals.

Close-up of layers of sedimentary rock in different shades of tan and brown. Photo by Alexander Schimmeck on Unsplash
  • When other rocks change because of extreme heat, pressure, or chemical changes, that makes metamorphic rock.

Dark rock with many layers. Photo by Josh Withers on Unsplash

Rock Uses and Examples

People use rocks for lots of different purposes! Some examples are:

  • Building materials: Granite is a mixture of quartz, feldspar, and mica. It's used to make countertops because it's hard, shiny, and pretty to look at.

Image of a kitchen with dark speckled countertops.

  • Concrete is a strong, hard rock used in building and construction. It's made of sand, limestone, basalt, cement, water, and more.

A wall made of concrete blocks with some weathering.

  • Road pavement is made of concrete, flagstone, bricks, asphalt, and more. It's used to make a smooth surface for cars to drive on.

Photo of a road with forests to the right and left and mountains in the background.

What is a Mineral?

A mineral is a natural solid that's a pure substance, meaning it's made entirely of one element (like carbon with the chemical symbol C) or compound (like sodium chloride, with the symbol NaCl — which is table salt!).

Don't be fooled! Rocks are mixtures of different substances, while minerals are made of one substance only.

To be a mineral, something must be:

icon of the earth with a long stem with a leaf around it.

  1. Naturally occurring — not made by people.

Icon of a rocky gray-brown mountain.

2. Inorganic — not containing carbon or made from living things' remains.

Icon of two ice cubes.

3. Solid — at room temperature, except for mercury.

Icon of sparkling crystals that are blue, purple, and pink.

4. Ordered, repeating pattern — like a crystal.

Icon of a chemistry flask with red bubbly liquid in it.

5. Made of the same chemical formula throughout.

If you have a sample that doesn't fit all of these descriptions, it's not a mineral — it's a rock!

Mineral Uses & Examples

People use minerals for many different things, like:

  • Gemstones used in jewelry. Purple quartz is called amethyst and yellow quartz is called citrine. Beryls are also minerals — emeralds are green beryls and sapphires are blue beryls.

Many gemstone rings in different shapes, sizes, and colors.

  • Makeup and other cosmetics. Mica is used for shimmer in eyeshadows. Talc is used to absorb oils and help makeup cover evenly.

A close-up of an eyeshadow palette with a rainbow of colors.

  • Decorations and money. Metal ores like copper, gold, and silver are also minerals. Gold leaf is used decoratively. Many ores are used for money, like silver dollar coins.

Close-up of a golden grate or tile with a floral pattern.

  • Staying healthy. We need to eat essential minerals to keep our bodies healthy. Calcium helps our bones be strong. Potassium helps keep our hearts beating.

Profile of a woman in athletic clothing doing a sit-up.

Minerals vs Rocks

A gif of a person's hands turning over a sample of rock. More rock samples are in the background.

Both rocks and minerals are naturally formed and are solids. Each one has unique properties that help us tell the difference!


  • Mixture of other rocks and minerals.

  • Have a varied look, like spots or stripes.

  • Can have dead plant or animal matter mixed in.

  • Used in building materials, roads, and more.


  • Made of one chemical.

  • Have a uniform look with one overall color.

  • Have a crystal structure.

  • Used in jewelry and cosmetics. Some are essential for the body.

So, Is a Diamond a Rock?

Now that we've learned about rocks and minerals, let's come back to our diamond.

Icon of blue diamond gem from the side with yellow sparkles.

  • Diamonds are solid.

  • They are made entirely of the element carbon.

  • Diamonds are not made of dead plant or animal matter.

  • They have a crystalline shape that makes them look shiny.

  • And, diamonds are naturally occurring.

Looks like our diamond fits all of the characteristics of a mineral!

It's not a rock after all!


Jordan found a pretty rock on a hike with their family. They're trying to figure out if it really is a rock or a mineral. Choose all the properties that tell you it's a rock:

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A smooth rock with googly eyes is on the top of a mountain and turns towards the camera.


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