Classify minerals using common mineral- identification techniques Explain special properties of minerals Describe what makes a mineral crystal a gem
How would you know if two minerals were different or the same? Color Luster Streak Cleavage and Fracture Hardness Density
Come in many different color and shades Same mineral can have a variety of colors Ex. Quartz is clear when pure Ex. When there are impurities it can be a variety of colors Weathering another form that affects color Pyrite or fools gold turns black
The way the surface reflects Shiny or dull Three types of luster Metallic- shiny or glassy Submetallic- dull Nonmetallic-dull
The color of a mineral in powdered form Streak plate made of unglazed porcelain Streak not always the same as the color Not affected by weathering More reliable then color
Cleavage is the tendency of some minerals to break along flat surfaces Gem cutters use natural cleavage to remove flaws Fracture is the tendency of some minerals to break unevenly along curved or irregular surfaces
A mineral’s resistance to being scratched Moh’s Hardness Scale Scratch the surface of a mineral with the edge of one of the 10 reference minerals If the reference mineral scratches the surface of your mineral, it is harder then your mineral
Hardness Common material Less that 2.5 mineral that marks paper 2.5 fingernail 3 copper penny 5 steel knife blade 6.5 steel file
Is how much matter there is a given amount of space Density(g/ cm 3 ) = mass (g) volume (cm 3 ) Water =1 g/cm 3 Specific gravity-ratio of an object’s density to water’s density Gold=19 19 times more matter in 1 cm 3 of gold than in 1 cm 3 of water
Fluorescence-calcite and fluorite glow under ultraviolet light Chemical reaction-calcite fizzes when a weak acid is placed on it Optical properties-thin clear calcite causes a double image
Radioactivity-uranium and radium detected by Geiger counter Magnetism-natural magnets Taste-Halite has a salty taste
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