Mineral Identification. Color Most notable characteristic Caused by presence of trace elements or...
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Transcript of Mineral Identification. Color Most notable characteristic Caused by presence of trace elements or...
Mineral Identification
Color
• Most notable characteristic
• Caused by presence of trace elements or compounds
• Least reliable way to identify a mineral because:– Different mineral can have same color– Same mineral can have different color
Luster
• the way a mineral reflects light
• can be either metallic or non metallic
• if non metallic it can be dull, pearly, waxy or silky.
Streak
• the color of the powder left behind when a mineral is rubbed on a streak plate.
• Does not always match the minerals color
• Minerals streak stays constant, even if weathered.
Hardness
• the measure of how easily a mineral can be scratched
• one of the most useful ways of identifying a mineral
• use Moh’s scale of hardness
Cleavage
• a mineral that breaks relatively easily, along even planes is considered to have cleavage
Fracture
• minerals that break with rough or jagged edges have fracture
http://academic.brooklyn.cuny.edu/geology/grocha/mineral/cleavage.html
Special properties
• Calcite – double refraction & fizzes w/ HCl
• Magnetite – magnetic
• Sulfur – smells like rotten eggs
• Halite – salty taste