4.2 Lecture Notes

Mineral Characteristics Tested

Magnetism Explain: The force of attraction between a magnet or a metal & magnetite.

4.2 Lecture Notes

Hardness Define: Resistance to scratching.

Method: Scratch mineral with objects on the Moh’sHardness scale.

4.2 Lecture Notes

Luster Define: The surface reflection of light.

Types:

Metallic: Shines like metal.

Non-Metallic: Glassy, earthy, chalky, or silky.

Acid Test Method: Put hydrochloric acid drops on amineral & see if it fizzes.

Fizzes = a carbonate mineral!

Crystal Shape

Describe: Well-formed crystals can havecharacteristic shapes.

Why the great variety of crystal shapes? - 88 naturally occurring elements

- made of atoms of differ sizes & properties that combine in many ways to form crystals.

-huge range of temperatures & pressures within the Earth contributes to this diversity.

But the variety is not endless: Certain shapes or variations occur again & again!

Density Define: Mass/Volume.

Method: Hold 2 same sized minerals. Which is heavier?

Heavier = more dense (has more mass/volume).

Specific GravityA mineral or rock’s density compared to water’s density which is a “1”.

Define:

pumice

obsidian

Streak

Method:

The color of a powdered mineral. It looks different than the original mineral chunk!

Swipe the mineral across a dull, white ceramic plate; look at the color of its mark.

Define:

Hematite vs. Pyrite

How a Mineral BreaksWhen Stressed Fracture:

Breaks along curvedsurfaces, splinters oruneven ways.

Define:

Describe Types:

Breaks in many directions.

Breaks along weakly bonded planes(not just some random mess)!!!

Cleavage:

Define:

Describe Types:

1. 1 direction

2. 2 directions

Sheet Mica

Long box with broken ends

3. 3 directions