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Identifying Minerals. Every mineral has certain identifying characteristics Color Streak Luster Density Hardness Crystal Systems Cleavage Fracture. Color . A great way to begin classifying minerals
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Identifying Minerals • Every mineral has certain identifying characteristics • Color • Streak • Luster • Density • Hardness • Crystal Systems • Cleavage Fracture
Color • A great way to begin classifying minerals • Can narrow down the search, but offers too little information to differentiate minerals of the same color
Streak • The color of a mineral’s powder • You can observe a mineral’s streak by rubbing a mineral against a piece of unglazed porcelain tile called a streak plate
Streak • A mineral’s streak does not always match its color • Ex. Pyrite “Fool’s Gold” = black streak • Ex. Gold = yellow streak
Luster • How light is reflected from a mineral’s surface • Examples: minerals that contain metals are shiny • Luster: metallic, glassy, waxy, greasy, pearly, dull, silky, earthy
Density • Density = the mass in a given space, or mass per unit volume • No matter the size of a mineral sample, the density will always be the same
Hardness • Mohs hardness scale ranks 10 minerals from softest to hardest • One of the best clues to identifying minerals is to test the hardness of the mineral • 10 minerals are: Talc is ranked as a 1 and a Diamond is the hardest known mineral that is ranked as a 10
Crystal Systems • The classification based on the number and angle of crystal faces • Ex. A cubic crystal system has 6 sides of all equal lengths --Magnetite
Cleavage • A mineral that splits easily along a flat surface has a property called cleavage (ex. Mica)
Fracture • Most minerals break irregularly, which is known as fracture • When you break the mineral, what does it look like?
Special Properties • Some minerals have unique properties like magnetism and fluorescence • Scheelite glows under ultraviolet light
Look at the Mineral on your table: • Answer the following questions about your mineral: • 1) What is its color • 2) Does it reflect light? • 3) Is it heavy or light? • 4) How hard is it? If you try to scratch it with your fingernail, does it leave a mark? • 5) How does the mineral break? • 6) Does the mineral have any other unique properties?