A crystal the size of a school bus? Dr. Michael A. Wise is a geologist, and an expert on pegmatites, at the Smithsonians National Museum of Natural History (Smithsonian Institution)
A crystal the size of a school bus?
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In South Dakota, miners found a crystal of a mineral. It is called spodumene. It was 42 feet long and weighed 90 tons. While it's an extreme example, the massive crystal showcased one of the incredible qualities of the rock in which it was found. It is known as "pegmatite." Unlike most rocks, pegmatites contain unusually large crystals of a wide variety of minerals.

Why?

Pegmatites are igneous rocks. They form as melted materials (magma) cool. This occurs far beneath the Earth's crust. Superheated water in the magma helps some chemical elements accumulate. That allows the magma to crystallize. Many minerals are created. Some are not found in most common rock types. Miners look to pegmatites for the beryl crystals. Those are cut into gems, like aquamarine. And the spectacular and colorful tourmaline.

But pegmatites produce more than just beautiful gemstones. Many minerals valued for industrial and commercial purposes are also found in pegmatites. Consider that your cellphone wouldn't work properly without the rare element tantalum. It is mined from pegmatites. That is the only rock where it occurs in high concentrations. Spodumene is the source of high-purity lithium. That is required for making rechargeable batteries. The muscovite found in mica-rich pegmatites is used in many products, including cosmetics.

Find out more about why Smithsonian Geologist Dr. Michael Wise calls pegmatites "Nature's Giant Treasure Chests."

Join us on Thursday, April 16, 2015, for a Smithsonian Science How live webcast. It's titled Mineral Dependence - Gemstones to Cellphones. It will air at 11 a.m. and 2 p.m. EDT on the Q?rius website. Mike Wise will appear live. He will discuss and answer questions. Get teaching resources to support your webcast experience.

Critical thinking challenge: How are we dependent upon minerals?

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COMMENTS (29)
  • Tiffany0307-yyca
    4/06/2015 - 10:07 p.m.

    That crystal-mineral rock does look fancy and is better than just ordinary yet pretty gemstones. It does kind of look like aquamarine and aquamarine is my birthstone. I can't believe that the crystal weighs (I think) more than a car! It must be the size of a giant (just a metaphor)! It think that the crystal is very unique because it is a special type of rock that belongs to the classification that is called "pegmatite". It's also very interesting to know how those pegmatite rock form. It's pretty much the most interesting thing I ever learned in science.
    Critical Thinking Challenge: How are we dependent upon minerals?
    Answer: It said in the passage that you can use it to make your phone work properly. Also minerals are also in our food.

  • KathrynH-Del
    4/07/2015 - 04:48 p.m.

    We need minerals for lithium to make rechargeable batteries for cellphones and iPads.

  • LylaH-1
    4/12/2015 - 01:44 a.m.

    In South Dakota, miners found a crystal of a mineral called spodumene. It was 42 feet long and weighed 90 tons. It is known as "pegmatite." Unlike most rocks, pegmatites contain unusually large crystals of a wide variety of minerals because they form as melted materials cool. This occurs far beneath the Earth's crust. Superheated water in the magma helps some chemical elements accumulate. Many minerals valued for industrial and commercial purposes are also found in pegmatites. Consider that your cellphone wouldn't work properly without the rare element tantalum. It is mined from pegmatites. I think it is amazing how large minerals can be. I wonder if there are crystals much larger in nature that we haven't discovered yet. This rare finding is a huge success.

  • felipevidal
    4/14/2015 - 10:31 p.m.

    This text talks about a big mineral called spodumene, it was found in South Dakota.

    I think this article is very interesting, I'd never hear about a mineral found somewhere in the earth could be so big, it's amazing to know it and get more knowledge about minerals.

    How are we dependent upon minerals?

    Well, we are very dependant on minerals, on almost every artefact we use in our life is made of minerals, like batteries, graphite pencils, pipes are made of copper even even sand is composed of little mineral pieces and with sand, we make glass.
    But the most important, cellphones and notebooks and every battery we use has a bit of lithium.

  • felipevidal
    4/14/2015 - 10:33 p.m.

    This text talks about a big mineral called spodumene, it was found in South Dakota.

    I think this article is very interesting, I'd never hear about a mineral found somewhere in the earth could be so big, it's amazing to know it and get more knowledge about minerals.

    How are we dependent upon minerals?

    Well, we are very dependant on minerals, on almost every artefact we use in our life is made of minerals, like batteries, graphite pencils, pipes are made of copper even even sand is composed of little mineral pieces and with sand, we make glass.
    But the most important, cellphones and notebooks and every battery we use has a bit of lithium.

  • LaurenO-Bru
    4/15/2015 - 09:58 a.m.

    The main idea of the story is about how these crystals and minerals are not only beautiful, but help us in real life situations. For example, our cellphones that we use have a rare element tantalum. Spodumene is also a source of lithium. Lithium is used to make rechargeable batteries. Muscotive found in pegamities is used in items such as cosmetics, also many other products. We use these crystals and minerals for almost everything.

  • Brayden-Hor
    4/15/2015 - 02:01 p.m.

    WOW!How do they get that big! I am AMAZED how they got that big!I have never got to see that big of a rock!Alright let me calm down for a second.

  • priscillap-Pen
    4/20/2015 - 11:55 a.m.

    1. Where was the crystal found?
    South Dakota.
    2. How big was the crystal?
    42 feet long.
    3. How is a pegmatite formed?
    They form as melted materials (magma) cool. This occurs far beneath the Earth's crust. Super heated water in the magma helps some chemical elements accumulate.
    4. Why might a fashion model need pegmatites?
    They are beautiful gems.
    5. Name 2 ways we are dependent on pegmatites.
    Its in rechargeable batteries and cosmetics.

  • mckenzieh-Pen
    4/20/2015 - 11:55 a.m.

    1. Where was the crystal found? South Dakota.
    2. How big was the crystal? 42 feet long and weighed 90 tons.
    3. How is a pegmatite formed? As melted materials cool.
    4. Why might a fashion model need pegmatites? They are beautiful gems.
    5. Name 2 ways we are dependent on pegmatites. It is in rechargeable batteries and it is in cosmetics.

  • matty-Pen
    4/20/2015 - 11:58 a.m.

    1. Where was the crystal found?south Dakota
    2. How big was the crystal?42 feet long and weighted 90 tons
    3. How is a pegmatite formed? They form as melted materials (magma) cool. This occurs far beneath the Earth's crust. Superheated water in the magma helps some chemical elements accumulate.
    4. Why might a fashion model need pegmatites?there beautiful gemstones they use it for rechargeable batteries and all the lights and stuff
    5. Name 2 ways we are dependent on pegmatites. That is required for making rechargeable batteries. The muscovite found in mica-rich pegmatites is used in many products, including cosmetics.

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