Rock Cycle - Rocks (1A)
 Lab 

   
OBJECTIVES:
  • Recognizing the differences between minerals and rocks.
  • Distinguishing minerals from rocks.
VOCABULARY:
  • crystal
  • mineral
  • pure
  • rock
MATERIALS:

Students sort rocks and minerals.


Miners exploring rocks in search of gold

BACKGROUND:

The Rock Cycle explains the evolution of igneous, sedimentary, and metamorphic rocks that make up the Earth’s crust. Many processes, such as volcanic activity, movement of the crust, and erosion and redeposition of rocks on the surface, create many different environments where different types of minerals and rocks form.

Minerals and rocks are important to our society. Many products made of minerals and rocks are a vital part of our everyday life. For example, concrete is a building material made of cement (calcite and clay) plus sand and gravel. In addition, gypsum is used for sheet rock or wall board in houses, gold for jewelry, and copper for wire.

It is difficult to distinguish minerals from rocks. Continuously doing exercises with the same minerals and rocks will allow students to internalize the difference.

PROCEDURE:
  1. Review the differences of rocks and minerals.
      
  2. Give each group of  students a bag of minerals and rocks. Instruct students to group the specimens into the following 3 piles:

    ROCKS - specimens that have the characteristics of rocks discussed in Pre Lab
    MINERALS
    - specimens that have the characteristics of minerals, discussed in Pre Lab
    DON'T KNOW
    - specimens that students cannot tell classify
     

  3. Give the students as much time as they need to examine the specimens. Encourage them to use a microscope or a hand lens. Go around the room and ask them if the specimens fit the characteristics of rocks or minerals. Make sure they are aware of the difficulties in the classification. Repeat the meaning of the characteristics many times, as they are hard for the students to understand and remember.
     
  4. If you are using the Rock Cycle - Rocks (1A) kit, you have the following minerals in each of the bags.

    QUARTZ - (clear) fits the "crystal" definition of MINERAL.
    HEMATITE
    - (shiny gray) fits the "pretty" definition of MINERAL.
    DOLOMITE
    - (solid white) fits the "pure color" definition of
    MINERAL.

    The remaining specimens in the bag are rocks. The students do not need to identify the rocks by name at this point.  The following rocks are included:

    MUDSTONE -  fine grained sedimentary rock
    SANDSTONE  - sand sized particles make up this sedimentary rock 
    LIMESTONE  -  composed of shell components make up this sedimentary rock
    SLATE -  flat, hard, dense compacted metamorphic rock
    SCHIST - shiny, flaking metamorphic rock
    GNEISS -  layered metamorphic rock
    BASALT - dark gray to black igneous rock
    GRANITE - large grained igneous rock
    RHYOLITE - light gray, fine grained igneous rock

  5. Encourage your students that they should classify the specimens in the "DON'T KNOW" group into either the mineral or rock groups. If they cannot classify some of them, leave them in the "DON’T KNOW" pile. Sometimes even geologists cannot identify a rock without using a microscope.

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