Rocks and Minerals Classification


Grade Level(s): 2/3


  • Classification of Rocks and Minerals
Duration: 50-60 minutes

Description:  Students are divided into station groups. Students will learn about the characteristics of rocks and minerals, how rocks and minerals are identified and classified, and finally the chemical properties of these rocks and minerals using an acid test.

Goals: Students will demonstrate an understanding of the characteristics and properties of rocks and minerals.

Objective(s): Students will:

  1. observe different classification characteristics and uses of rocks and minerals
  2. identify different rocks and minerals

 California State Standard-Earth Science:

3. Earth is made of materials that have distinct properties and provide resources for human activities.
As the basis for understanding this concept, students know:
a. how to compare the physical properties of different kinds of rocks and that rock is composed of different combinations of minerals.
b. smaller rocks come from the breakage and weathering of larger rocks.
c. soil is made partly from weathered rock and partly from organic materials, and that soils differ in their color, texture, capacity to retain water, and ability to support the growth of many kinds of plants.

  • Materials for Station 1:
    aluminum foil  vitamins  soda can coins
    film  wiring cement food
    batteries  paints  items not
    made of minerals
    nails china glass animal feed
    salt  mortar  mirrors magnets 
    •  Poster on Rocks and Minerals and How We Use Them
  • Materials for Station 2:
    • rock and mineral box
    • igneous (granite, obsidian, basalt and pumice)
    • metamorphic (slate, marble and staurolite)
    • sedimentary (shale, brachiopod limestone and sandstone)
    • minerals
    • 5 hand lenses
    • copper penny
    • nail
    • fingernail
  • Materials for Station 3:
    • paper towels
    • 5 labeled rock samples
    • hand lenses
    • 5 droppers
    • 1 cup vinegar
    • five dishes

3 parent volunteers per class

Background: Click here for background.

Rocks are aggregates of one or more minerals and are classified by how they were formed (a mineral is a homogenous crystalline chemical element or compound and is classified according to physical characteristics).

Introduction:  5 minutes

The volunteers should review the background information prior to the activity. Introduce volunteers to class. Two volunteers will set up the three stations while the third volunteer speaks with the class. Ask the students "What do you know about rocks and minerals?  Where do they come from?" Accept all answers. Ask the students "Why should we learn about rocks and minerals?" Divide the class into three groups and assign one volunteer to each group. The groups will rotate through the three stations.

Station 1: Learning About Rocks (15 minutes)

Show the group items in the box of products. Some of the items will list ingredients, read over these with the students and let them discuss where that ingredient originates from and what function does it have in the product.  Can the students identify items not made of minerals? Ask the class if they can think of other uses for minerals. Refer to the  the Rocks and Mineral poster.

Encourage them to discuss the major role rocks and minerals play in helping us maintain and improve our way of life; can the students list ways rocks are used in agriculture, arts, communication, construction, consumer goods, energy, manufacturing, medicine, transportation and science and technology?  Guide and encourage their responses.  If they look around the room, can they identify items that are made from rock or minerals, or
distinguish between those things that are not made of rock or mineral materials?  Continue to look over the poster of Rocks and Mineral as the students discuss more ways in which we use this resource.

Station 2: How Rocks are Classified:  (20 minutes)

In this station students will look at samples from the rock and mineral box.
Take the group through one box at a time.

Igneous Rocks

  • Granite, obsidian, pumice and basalt are examples of igneous rocks.
Let all the students handle the rock samples and look at them with the hand lenses. Have students describe the color, texture, shape, weight etc. Ask the students why some rocks are smoother than others are.
(Round and smooth rocks have been moved and formed by water and ice).  See if the students can pick out obsidian, a shinny, black and very smooth, glass like rock.  Next, let them discover the characteristics of pumice relative to the other types of rocks (pumice is a rock that will float in water). As they are looking at the rocks, ask bout weight, flexibility, texture, size, shape and the other properties that we can use to classify rocks.
Encourage them to compare the rocks. With the background information as reference, discuss with the students how igneous rocks are formed.

Metamorphic Rocks

  • Slate, marble and quartzite are examples of metamorphic rocks.
Let the students explore all the metamorphic rocks and try to identify them using the field guidebooks and hand lenses. Ask them to describe what they see. Are some of the rocks very similar to others?  Can they see any signs of intense weathering on some of the rock? What may have given the rock samples their shape? Discuss the background information with the students and let them compare and contrast metamorphic with igneous. Be careful not to mix up the rocks from one box to another.

Sedimentary Rocks

  • Sandstone, shale and limestone are examples of sedimentary rocks.
The most familiar type of sedimentary rock found  is sandstone. Ask the students where the sand comes from in this process. Review briefly how sedimentary rocks are formed. Let the students explore all the rocks and try to identify them using the field guidebooks and hand lenses. Have the students look at all the layer lines in the sedimentary rock samples.  Ask them to imagine the pressing and cementing together to form this rock.

Station 3: Experiments: The Acid  (20 minutes)


Rocks are classified into three main groups depending on how they are formed. Sedimentary rocks are made from sand and silt that have been pressed together into layers.  Igneous rocks are rocks that became so hot that they melted, then cooled down and solidified again.  Metamorphic rocks are sedimentary or igneous rocks that have been altered by the action of heat or pressure.  There are many ways that rocks can be changed.  Igneous rocks beneath or on the Earth's surface are constantly subjected to physical and chemical conditions that change them. As a result of these changes, sedimentary rocks, metamorphic rocks, or new igneous rocks are formed. Students should be able to describe and characterize different types of common rocks, use a guidebook to identify rocks and minerals and be aware of the many uses for rocks and minerals in today's world.