1. Chapter 3 Section 5 What are some other ways to identify minerals? Objective: Explain how density, magnetism, and an acid test can be used to identify minerals.

2. Key Terms density: amount of matter in a given volume magnetism: force of attraction or repulsion associated with magnets acid test: test that helps identify minerals containing calcium carbonate

3. Density All matter has mass and volume. You can calculate the density of an object by using the following formula: Density = Mass Volume

4. Density As an example, suppose that you have a sample of the mineral talc. Your sample has a mass of 26 g and a volume of 10 cm 3. It you divide 26 g by 10 cm 3, you will get a density of 2.6 g/cm 3.

5. Density Density is a property of minerals that never changes. For this reason, density can be used to help identify minerals. Density is measured in grams per cubic centimeter, or g/cm 3. Most minerals have a density that measures between 2 and 3 g/cm 3.

6. 1. EXPLAIN: How can density be used to identify minerals?

7. Magnetism Magnetism is displayed when objects made of iron, nickel, or cobalt are attracted to a magnet. Steel, which is an alloy of iron, also shows magnetism. Magnetite is a mineral that contains iron. If you held a small chunk of magnetite near a magnet, the magnetite would be attracted to the magnet. Magnetite can also sometimes act as a magnet itself. Magnetite shows the property of magnetism.

8. 2. EXPLAIN: How could you use a magnet to determine if an unknown mineral is magnetite?

9. The Acid Test Some minerals contain calcium carbonate (CaCO 3 ). Knowing that a mineral contains this compound can help you identify the mineral. To test for calcium carbonate in a mineral, you place a drop of a weak acid on a small piece of the mineral. If the surface of the mineral fizzes, the mineral contains calcium carbonate. This is the acid test. Calcite and dolomite are two minerals that contain calcium carbonate.

10. 3. EXPLAIN: What is the acid test?

11. Classwork CHECKING CONCEPTS 1. What is density? 2. Which common mineral is attracted to a magnet? 3. What kind of minerals can be identified by the acid test?

12. Classwork THINKING CRITICALLY 4. IDENTIFY: What two properties must be known to calculate the density of a mineral? 5. CALCULATE: What is the density of an object with a mass of 49 g and a volume of 7 cm 3 ? 6. ANALYZE: How can the property of magnetism be used to help you identify two gray minerals?