2. Properties of Rocks Lesson 1

3. What you will learn today What the words homogeneous and heterogeneous meanWhat the words homogeneous and heterogeneous mean What makes a rock a rockWhat makes a rock a rock

4. Homogeneous minerals They have a unique crystalline structure and specific hardness-just like this close-up of sandstoneThey have a unique crystalline structure and specific hardness-just like this close-up of sandstone See the crystals?

5. What does Heterogeneous Mean? Rocks are a made up of more than one mineral.Rocks are a made up of more than one mineral. FeldsparMicaQuartz Granite + +=

6. Properties of Rocks There are five five properties which help identify rocks: Hardness Luster Color Streak Density

7. Hardness 200 years ago Friedrich Mohs devised a scale by which the hardness of minerals could be ranked from 1 to 10.

8. ROCK JOKE What is a rock’s favorite transportation? A rocket!

9. At the high end (10) Mohs put the hardest mineral, the diamond

10. At the low end (1) Mohs put talc which is the softest mineral

11. How To Test Hardness The hardness of a mineral can be tested by doing a scratch testThe hardness of a mineral can be tested by doing a scratch test Many minerals do not go higher Many minerals do not go higher than 7 or 8 than 7 or 8

12. Hardness Scale If your fingernail easily scratches the mineral, it is a 1If your fingernail easily scratches the mineral, it is a 1

13. If glass can scratch the mineral, it is a 5

14. If quartz can scratch the mineral it is a 7

15. Luster Describes the appearance of the mineral’s surface Is it shiny? Is it dull? Is it waxy? Is it glassy?

16. Describes characteristics of color and color combinations

17. Streak Streak describes the color left by the rock when drawn across hard surface This type of test helps when trying to identify dark looking minerals.

18. Density Describes the weight of the rock. Gold has a density of 19 Talc has a density of 2.7 The density of water is 1

19. What does homogeneous mean? What does heterogeneous mean? What are the 5 properties of a rock?

20. Thanks goes to: Sues’ Gemstones for the diamond pictures Intel for creating a microscope that hooks into the computer for the close up pictures