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