Rare minerals from pegmatites

  • Exhibition Text

    • As molten granite crystallizes, the melt that remains becomes enriched in water and rare elements such as boron, lithium, tantalum, and niobium. These elements concentrate in the melt because they are not taken up by the minerals crystallizing from it. Eventually, enough water builds up that steam forms. Gem and ore minerals containing rare elements form in the pockets of steam- and water-rich melt. In the presence of water, minerals can grow to enormous sizes, forming rocks known as pegmatites.

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  • For Educators

    • Topic: Earth Science

      Subtopic: Minerals and Resources

      Keywords: Magmas, Natural resources, Hydrogeology, Chemical elements, Pegmatites

      Audience: General

In This Section

Tourmaline pegmatite

Tourmaline pegmatite

The large groups of pink crystals of the boron-bearing mineral tourmaline and the tiny purple crystals of the lithium-bearing mineral lepidolite grew from a melt consisting of lithium, boron, and water-rich silicate.