Crystals A solid substance in which the particles, or pieces, are arranged in one of 6repeatable patterns when molten minerals solidify or when the liquid evaporates from a solution. • Most minerals are composed of crystals. • Crystals come in 6 different shapes. • Some can be seen with your eye or magnifier, but others can only be viewed with special X-Ray equipment.
Crystals Form in One of 6 Shapes Cubic • How do you think a geologist might use crystals to identify minerals? • Do you think you can correctly identify the shape of each of your minerals? • It can be very difficult to identify the shape of the crystals in all of your minerals because not all samples will have well developed crystals. Geologists will sometimes have to use very sophisticated equipment to identify the crystals shape.
Class Activity • Each student will cut and tape one of each crystal shape. • Your teacher will then tape them all together to form mineral models.
Data Collection Next useyour magnifying glasses, I want you to examine your minerals and see if you can identify the shape of their crystals. Record your observations in your binder.
Salt Crystals Salt crystals are referred to as a cubic crystal because they are a pattern of cubes. The shape of a crystal is the repeating pattern of the particles that make it up. The salt crystals only have one pattern of crystals and they are cubic. Each mineral can contain only one crystal shape. The crystal shape of a mineral will be the same no mater where on earth you find that mineral. Salt crystals are cubic no matter where you find them.