1. Minerals, rocks and resources
Reviewing ch. 2
Minerals, rocks and resources

2. Minerals:
Inorganic, solid, naturally occurring, with well-defined properties.
Minerals can be identified based on:
Color (not so good!)
Luster (metallic? Nonmetallic?)
Streak (rub against a tile!)
Crystal Structure (regularly-shaped…not the same as cleavage!)
Hardness (scratch it against a substance of known hardness.)
Cleavage vs. Fracture (when it is hit with a hammer, are there smooth, flat surfaces or irregular ones?)
Density (g/ml)
Unusual properties (Tastes salty? Double vision? Magnetic? Radioactive?)

3. Rocks: Made of one or more minerals.
Are identified based on their origin. (molten material? sediments? Other rocks?)
The “texture” of the rock is the most helpful feature.

4. Igneous Rocks: Always form from molten material (lava or magma).
Size of crystal = how the rock formed.
Large crystals = plutonic (intrusive) rocks that had a L O N G time to cool.
Small crystals = volcanic (extrusive) rocks that cooled quickly.
No crystals = extremely rapid cooling at the surface.
Some extrusive ones also have gas pockets (vesicular)

5. (other igneous rock characteristics)
The other differences within igneous rocks includes their “ingredients” – or minerals.
Mafic = made of denser, darker minerals. (see p. 6 in the ESRTs!)
Felsic = lighter minerals.
There are some minerals that are found in both.

6. Sedimentary Rocks: Usually have sediments – sometimes in layers.
Divided into 3 categories (see p. 7 in the ESRTs!).
CLASTIC = made of sediments weathered off of rocks on land.
CRYSTALLINE/CHEMICAL = made from minerals that were dissolved in seawater.
ORGANIC = made from remains of plants/animals.

7. More about sed. rocks:
CLASTIC =Identified by their GRAIN SIZE – not composition!
CRYSTALLINE = identified by their COMPOSITION – not grain size!
ORGANIC = also id’d by composition – not grain size.

8. Metamorphic Rocks:
These are formed when ANY rock gets CHANGED by heat or pressure.
Divided into 2 categories based on texture (see p. 7 in the ESRTs).
FOLIATED = banding or mineral alignment. These have very strange layers (not like the sed. Rocks!)
NONFOLIATED = not like the foliated ones.

9. (more about Meta. Rocks…)
The FOLIATED rocks all form from REGIONAL metamorphism – when a great deal of pressure squeezed the rocks.
The NONFOLIATED rocks may form by either CONTACT or REGIONAL metamorphism.
CONTACT meta. Is when hot lava or magma touched rocks and altered them (but DIDN’T MELT THEM!)

10. Rock Cycle: See p. 6 in the ESRTs.
Essentially, any rock can change into another if it goes through certain steps.
For example: Igneous rocks start as the solidification of molten material.
Many sedimentary rocks start from sediments weathered from rocks.
Metamorphic rocks are changed by heat/pressure.

11. Natural Resources
Renewable = can be replaced after use. (trees, wind, solar power…)
Nonrenewable = not going to come back in our lifetime! (fossil fuels, ores, …)
We should look for more renewable energy sources!