BIG IDEA: Rocks and minerals have properties that can be: observed, tested, described, identified and recorded.

o What does the object look like? o Where have you seen it before? o What is it used for? o What do you think it is?

Our Principal was very pleased to see that you were able to identify the 10 minerals in the collection and can’t wait for you to identify the remaining rocks. But, before we begin identifying the remaining rocks, our Geologist has asked us to look at one other way to identify minerals. The geologist said that many minerals can also be identified by observing a property we have not investigated. Most minerals are composed of crystals. Crystals come in different shapes and some of the crystals and there shape can be seen with your eye or magnifier, but others can only be viewed with special X-Ray equipment. The geologist has sent some information and materials so you can investigate how crystals and there shape might be important in identifying materials. What does the principal and geologist want us to do? What did the geologist give us to help? What is the problem we need to solve?

How can we…

We have already been able to identify the 10 minerals in our principal’s collection, but now the Geologist is asking us to investigate another way to identify minerals by looking at their crystals. How many of you are familiar with the term crystal? Crystal A solid substance in which the particles, or pieces, are arranged in one of 6 repeatable patterns.

I think that we can…because… Before we begin looking at our new information and materials, I would like you to write a prediction. I want you to think about and explain, the role crystals, and their shape, may have in identifying minerals.

I am going to share with you some of the information and materials the geologist has sent to help us investigate how crystals and their shape can be used to identify minerals. I am going to give each group a lid with some tiny crystals. Using your magnifiers I want you to examine and describe the properties of these crystals with your group. You should include a detailed drawing with labels in your scientist notebook. What shape are these tiny crystals? What do they remind you of?

The tiny crystals you just observed were salt crystals and they 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. Crystals come in 6 different shapes. Even though some may be larger than others they will always exist as one of these shapes.

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.

Using your 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 scientist notebook. Crystal Shapes of Minerals Cubic TetragonalHexagonal Orthorhombic MonoclinicTriclinic

How can a geologist identify a mineral by its crystals?