Identifying Minerals

What Is a Mineral?

Did you know that minerals are all around us? Minerals are the building blocks that make up rocks. They are the ores that we extract metals and rare elements from to make electronics. They're even in the soils that we need to grow the plants that we eat for food. They're in our jewelry. They're even in glitter used for makeup.

Hi, my name is Gabriela. I'm a scientist who studies minerals, a mineralogist here at the National Museum of Natural History. You know, we have a lot in common. You know how to make observations and find patterns in the world around you. That's the work of a scientist.

Right now, I'm standing in front of a mineral specimen from our National Gem and Mineral Collection. This is the Berns Quartz. Let's figure out what makes quartz a mineral.

What is a mineral? Let's make a checklist. First, a mineral is a solid. In other words, a mineral cannot be a liquid or a gas. See, this quartz crystal is solid. Second, a mineral is made up of consistent ingredients called atoms. In the case of quartz, quartz is made up of two kinds of atoms called silicon and oxygen. Third on our checklist, a mineral has to be a crystal. A crystal is made when trillions of atoms come together in a repeating, precise arrangement. In the case of quartz, the atoms come together like this. Fourth, a mineral has to be naturally occurring, which means that it's made by the Earth and found outside. It cannot be something that is only made in a laboratory. For example, the Berns Quartz was dug out of a mine in Arkansas. Finally, number five on our checklist. Minerals are inorganic, which means that they are formed by the Earth through geological processes.

Minerals are not organic, which means that they are not formed by plants or animals.

Here I’ve assembled some examples of different minerals. Note how they all have different crystal shapes, they come in different colors, and amazingly, they are formed naturally by the Earth. They were all discovered in mines from all around the world.

However, there is one example here that's not a mineral. Let's figure out why. This is amber. It's fossilized tree sap, which means that it's made by a plant. And so it can't be a mineral.

Now it's your turn to be a mineralogist. Let's go through our checklist. First, all of these mineral specimens are solids. Second, all of these minerals are made up of consistent ingredients. For example, this pyrite is made up of atoms called iron and sulfur. This is only made up of sulfur. Now, it's those chemical ingredients that give these minerals their different colors. Third, all of these minerals are crystals. Look at how they all have different crystal shapes, different crystal structures. For example, this pyrite is a cubic structure. It looks like a cube, whereas this beryl has a hexagonal structure. It makes a hexagon. Fourth, these minerals were all made by the Earth, naturally. they were discovered in mines from around the world, like from Spain. This is from the United States. And this is from Peru. Finally, number five, all of these minerals are inorganic.

You did a great job, mineralogists.

Remember, apart from sunlight, and the air we breathe, almost everything that we interact with in our daily lives involves minerals in some way.

Now that you know how to identify minerals, I hope that you start to notice them in the world around you, just like me.

Virtually explore the Janet Annenberg Hooker Hall of Geology, Gems, and Minerals.

We will not be covering volcanoes, earthquakes, or plate tectonics during our digital school program, but NMNH has several related resources to support your teaching. 

• Video: Volcanoes and Pyroclastic Flows – Join Geologist Dr. Ben Andrews to explore volcanoes and pyroclastic flows — the super-heated gas and ash that is erupted during explosive volcanic eruptions. Ben describes how these eruptions happen, what causes ash and other materials to explode, and how scientists like him study active volcanoes and pyroclastic flows.
• Video: How Volcanic Eruptions Send Materials Up and Out – This video features Dr. Ben Andrews, a geologist at the National Museum of Natural History. He studies volcanoes to get a better understanding of how eruptions happen. What causes ash and other materials during violent "pyroclastic" eruptions to spew out the way they do? Explore the physics of explosive eruptions. Reflect on the hazards scientists face in studying active volcanoes. Visit Ben's volcanology lab to see how he uses his simulator — a giant tank, talcum powder, lasers, and cameras — to model how erupted materials travel. Understand why research on volcanoes is important for our safety.
• Video: Plate Tectonics – See how mapping the location of volcanic eruptions and earthquakes can tell us where tectonic plate boundaries are. Dr. Elizabeth Cottrell explains how the plates interact and how volcanic eruptions actually cause earthquakes.
• Video: Volcano Geochemistry: Windows to Earth's Interior – This video features Dr. Elizabeth Cottrell, a geologist at the National Museum of Natural History. Explore volcanoes as windows into the Earth's interior. Understand how you are connected to the interior of the Earth. Uncover the evidence about geologic events contained in volcanic glass. Think about how plate tectonics have gotten us to where we are today.

Featured Collection: All Sorts of Quartz – Quartz is one of the most abundant minerals in the Earth’s crust and is found on all continents. It exists in a variety of forms and colors, and has many uses. In this collection of museum specimens, you’ll explore the diversity of quartz.