## Shapes of Mineral Crystals

 Cubic crystals are not always cube shaped! There are many that are shaped like octahedrons (eight faces), and some that are shaped like dodecahedrons (12 faces). Tetragonal crystals are shaped like cubic crystals but are longer in one direction making shapes like double pyramids and prisms. Orthorhombic crystals are often shaped like rhombic prisms or dipyramids (two pyramids stuck together). They often look a bit like tetragonal crystals except that they are not square in cross section (when you look at the crystal on end). Hexagonal crystals often look like six-sided prisms. When you look at the crystal on end, it looks like a hexagon shape in cross section. Monoclinic crystals look like tetragonal crystals that have been skewed. Often, they form prism shapes and double pyramids. Triclinic crystals are sometimes very strange shapes! They are usually not symmetrical from one side to the other.

## Shapes of Mineral Crystals

 Cubic crystals are not always cube shaped! There are many that are shaped like octahedrons (eight faces), and some that are shaped like dodecahedrons (12 faces). Tetragonal crystals are shaped like cubic crystals but are longer in one direction making shapes like double pyramids and prisms. Orthorhombic crystals are often shaped like rhombic prisms or dipyramids (two pyramids stuck together). They often look a bit like tetragonal crystals except that they are not square in cross section (when you look at the crystal on end). Hexagonal crystals often look like six-sided prisms. When you look at the crystal on end, it looks like a hexagon shape in cross section. Monoclinic crystals look like tetragonal crystals that have been skewed. They often form prism shapes and double pyramids. Triclinic crystals are sometimes very strange shapes! They are usually not symmetrical from one side to the other.

## Shapes of Mineral Crystals

Some mineral crystals have six sides. Others have eight sides, 10 sides, or even more! How many sides do the minerals in your collection have?

These pictures show some of the shapes that minerals can have. Do any of your minerals have these shapes?

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