Catalyst

1. Catalyst • Put Safety Quiz, Safety Contract, and DonorsChoose form (if applicable) in front of you. • I will check them off. • Catalyst Question: Based on the four characteristics of minerals, how do you think geologists identify different minerals?

2. Agenda • Catalyst • Announcements • Mini-Lesson: Identifying Minerals • Lab: Geologist for a Day • Alternative: Mineral Packet • Work Time (Foldables) • Closing • Exit Ticket

3. Foldable • Be sure that by the end of class on Thursday (10/25) you have completed your foldable on silicates, carbonates, and oxides. • I will be collecting/marking them. Only marked foldables may be used on the quiz. • If you were absent, see me during work time.

4. Science Fair Part 2 (100 points) • Up to 90% credit today • Be sure to stay up-to-date!

5. Identifying Minerals

6. Objective • By the end of class, CWBAT create a lab procedure to determine the identities of unknown minerals. • CCSS Reading Grades 11-12 • Follow precisely a complex multistep procedure when carrying out experiments, taking measurements, or performing technical tasks; analyze the specific results based on explanations in the text. • CRS Scientific Investigation: 28-32 • Determine the hypothesis for an experiment. • Assessments: • Assessed in creation of lab procedure/completion of packet.

7. Basics • More than 3000 minerals in Earth’s crust • How do you identify so many? • Use a combination of tests!

8. Tests • Color • Luster • Texture • Streak • Hardness • Cleavage/Fracture • Density/Specific Gravity • Special Properties

9. 1. Color These all have the same chemical composition , they just contain different trace elements! • Most noticeable characteristic • Can be due to the presence of trace elements • Quartz types • Rose quartz (pink) contains manganese or titanium • Jasper (red) contains iron oxides • Amethyst (purple) contains ferric iron • Citrine (orange) contains iron hydrates • All of these are quartz! • The least reliable way to identify a mineral

10. 2. Luster • The way a mineral reflects light from its surface. • Described as either • Metallic • Nonmetallic

11. 2. Luster Metallic Nonmetallic Not shiny; described as dull, pearly, waxy, or silky Examples: Calcite, gypsum, sulfur, quartz • Shiny; reflects like chrome on a car • Examples: • Copper, silver, gold, galena

12. 3. Texture • How a mineral feels to the touch • Descriptions: • Smooth • Rough • Ragged • Greasy • Soapy • Glassy

13. 4. Streak • The color of a mineral when it is broken up and powdered. • Determine by rubbing across an unglazed porcelain plate • Will not always be the same as the external color!

14. 5. Hardness • Measure of how easily a mineral can be scratched • Mohs Scale of Hardness • Based on known hardness of 10 minerals • 1: Talc (scratched by fingernail) • 10: Diamond (scratches all common objects) • One of the most useful tests

15. 5. Hardness copper coin the side of a steel nail Leaves mark on a streak plate

16. 6. Cleavage & Fracture • How minerals break is determined by atomic arrangement. • Minerals split along planes where atomic bonding is relatively weak.

17. 6. Cleavage & Fracture • Cleavage • A mineral has cleavage when it splits relatively easily and evenly along one or more flat planes. • Examples: • Mica • Perfect cleavage in one direction • Halite • Cubic cleavage (breaks in 3 directions)

18. 6. Cleavage & Fracture • Fracture • When minerals break with rough or jagged edges • Examples: • Quartz • Uneven breaks along jagged edges due to tightly bonded atoms* • Rock obsidian • Conchoidal fractures (arc-like patterns resembling clam shells)

19. 7. Density & Specific Gravity • When you lift two equally-sized minerals and one feels heavier. • Density • D = M/V • Reflects atomic weight and structure of a mineral • Specific Gravity • More accurate than estimates of density • S.G.= weight of substance/weight of equal volume of water at 4°C

20. 8. Special Properties • Double refraction • Causes 1 ray of light to bend in 2 directions • Calcite, Iceland spar • Reaction with HCl • Reaction creates bubbles of CO2 • Calcite (calcium carbonate) • Magnetism • Acts like a magnet • Magnetite, lodestone • Odor • Rotten egg smell • Sphalerite, sulfur • Volunteer needed! 

21. Lab Instructions • Contacts out • Hair tied back • Absolutely NO • Gum • Food • Drinks (even water!) • If you did not turn in your forms, gather near the whiteboard for further instructions.

22. Lab Instructions • Read pages 92-93 • Silently/independently • Groups of three • 1) Supervisor • Gathers materials/responsible for directions being followed • Leads group through experiments • 2) Data Manager • Create chart/write • 3) Primary Experimenter • Carry out tests • Acid, nail, etc.

23. Lab Instruction Changes • On sheet in basket: • Magnifying glass (x1) • Add “Paper clip (x1)

24. Lab Instructions • Answer Questions: • Plan the Experiment • #1, 3, 4 • Analyze • #1-4 • Make sure that you have a hypothesis, chart, and write-up of the questions. • When finished, raise your hand.

25. Work Time: Foldables • Use pages 81-83

26. Review Objective • By the end of class, CWBAT create a lab procedure to determine the identities of unknown minerals.

27. Exit Ticket • On the back of your Catalyst sheet… • What are the most reliable ways to determine the identity of a mineral sample? • What are the least reliable ways?