How to Identify Minerals…

Diet & NutritionCalcium, Chlorine, Chromium, Copper, Fluoride,

Iodine, Iron, Magnesium, Potassium, Sodium, vitamins

Kidney stones, gallstonesWaterCarsBatteries – MP3 players, iPods, cell phonesElectricityJewelryFool’s gold

Why should we know about minerals?

What characteristics would you use to identify or classify different minerals? (3,800 minerals)

9 classifications/properties (physical & chemical properties)

Identifying Minerals

Easy to observeNot always a clear way to identify

Color

Streak: the color of its powderColors of minerals may vary but streak does

not

Streak

Luster: how much light is reflected from a mineral’s surface

Luster

Metallic - Galena

Glassy - Topaz Waxy, greasy, or pearly - Talc

Submetallic/dull - graphite

Silky - Malachite Earthy - Hematite

Density: how much mass there is in a given space

D = m/v or water displacement

Density

Hardness: determined by a scratch test A mineral can scratch any material softer than

itselfBut can be scratched by any mineral that is

harderMohs hardness scale

Hardness

Mohs Hardness Scale

Crystal system: the structure of how the mineral’s atoms form

Ex: cubic, hexagonal, rhombic

Crystal Systems

Cleavage: when a mineral splits along a flat surface

Ex: Mica

Cleavage

Fracture: when a mineral breaks apart in an irregular way

Fracture

Some minerals are identified by special physical/chemical properties.

Special Properties

Person #1: describe rock to partner using 3-4 properties

Switch

Group Identification

Review A. Usually not a clear identifier

B. Does not break in a flat sheet

C. Calcite’s powder is always white

D. FluorescentE. Breaks in flat sheetsF. Shiny mineralG. Cubic shapeH. Compares how it is

scratched/scratchesI. How much mass takes up

a certain volume

1. Color2. Streak3. Luster4. Density5. Hardness6. Crystal system7. Cleavage8. Fracture9. Special properties

Answers: 1. A 2. C 3. F 4. I 5. H 6. G 7. E 8. B 9. D