Do Now – SILENTLY! • Take out your agenda Sheet, Science folder, packet, and 2 pencils • What is a mineral? (Write all 5 characteristics) • Draw a picture of a mineral.
Look at the following minerals. Which do you think are the same types of minerals and which do you think are different?
HAHA! I tricked you! • These are all the SAME type of mineral! These are all examples of the mineral QUARTZ!
Why is it so difficult to tell minerals apart!? • There are at least 4,000 minerals that we know of in the Earth’s crust • As you can see with quartz, often times the same kind of mineral can look very different! • Therefore, geologists use several types of tests to determine the type of mineral they have found!
How to identify minerals • There are many different ways, but we will explore the main ways!
Today’s objective • Know: Mineral Identification • Show: Explain how minerals are identified by their properties • LOT: Comprehension
Color • Color is the most noticeable characteristic of a mineral. However, it is also the least reliable characteristic.
Color • With the colored pencils at your desk, draw a picture of two different minerals of two different colors (like Quartz)
Streak Streak is the color of the line a mineral makes when it is scraped on a tile. (This is a better clue to a mineral’s identity than the surface color.)
Streak Draw a picture: Fun fact: one way to tell the difference between pyrite (Fool’s gold) and real gold is by streak. Pyrite leaves a greenish-black streak while real gold leaves a yellow streak.
Luster • Luster is the way a mineral reflects light from its surface. The two types of luster are: • Metallic • Non-Metallic
Luster – 2 types! Draw a picture: Metallic: Non-Metallic:
Hardness • Hardness is a measure of how easily a mineral can be scratched. • Measured on Mohs scale 1-10
Mohs Scale – Fun facts! • Your fingernail has a hardness of about 2.5 • A steel file has a harness of about 6.5 • A diamond is the hardness mineral only another diamond can scratch a diamond
Hardness Draw a picture
How a mineral breaks A mineral can break in two ways: • Cleavage: breaks into regular, flat pieces • Fracture: breaks into irregular, jagged pieces.
How a mineral breaks Cleavage Fracture
What are the different ways we can test a mineral?????? There are FIVE major ways!
The tests: • COLOR • LUSTER: Metallic or Non-Metallic • STREAK: color on tile • HARDNESS: Mohs’ scale • How a mineral b-r-e-a-k-s: cleavage or fracture
CFU! • What is the least most reliable of all the properties? Why? • What is the difference between cleavage and fracture? • What would happen if you rubbed a mineral of a Mohs’ value 7 with a Mohs’ value 5?
Let’s Brain Pop! First watchThen fill out the quiz! • http://www.brainpop.com/science/earthsystem/mineralidentification/
CFU • What is the streak test? How do you perform it? • What are the two different types of luster? How do you know which is which? • Challenge question: Any other ideas of how we could test minerals!?!?!!?
How else can we tell minerals apart? • DENSITY! (how tightly packed it is!) • ACID Test! (might form bubbles) • Fluorescence (normal light vs. ultraviolet light)