2013_05Minerals - Minerals Unless specied otherwise, all...

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MineralsUnless specified otherwise, all photos, images, &figures in this presentation are courtesy of W. W.Norton.Know thedefinition of a mineral.Understand the basicphysical properties of mineralsand how to apply them.Be familiar with theparts of an atom.Understand the differenttypes of bonding.Know the differences betweenanions & cations,polymorphs & isotopes, andatomic number & atomic weight.Learn about thesilica tetrahedronand how it linkages in silicate minerals impartsome of their physical properties.Some key points to keep in mind...
Amineralis defined as a substance that meets the following 5 criteria:solidnaturally occurring (nothing synthetic)mostly inorganic (not coal--mineral resource)a definite chemical composition (minor substitutions)a definite crystalline structure (not disorderly-glass)Rocksare an aggregate of minerals.Mineralsa definite chemical composition (minor substitutions)Minerals
a definite crystalline structure(not disorderly-glass)Ordered atoms in crystals form alattice(patterns that repeat in 3 dimensions).This internal pattern controls mineral properties:Crystal shapeSymmetryCleavageMineralsglassCharacteristics determined by your 5sensesUsed to ID mineralsProperties depend upon…Chemical composition.Crystal structure.Some are diagnostic.Example:Pyrite (FeS2)Cubic crystals, high specific gravity, striated crystal faces,black streak, metallic luster, dull brassy color, sulfur smellwhen crushed, erroneously mistaken for gold (fool’s gold).Minerals have a unique set of physicalproperties(just like individuals in this classroom).MineralsPhysical PropertiesPyriteColorLusterStreakHardnessSpecific GravityCrystal FormFractureCleavageStriationsTenacityReaction to HClacidMagnetismTasteOdorFeelCommon Physical Properties
The appearance of a fresh mineral surface inreflected light is theluster.MineralsPhysical PropertiesMetallic LusterNon-Metallic LusterMetallicfreshly broken metalSub-Metallicdull metalDon't confuse with dark glassyminerals!VitreousglassyResinousresin-like, waxyPearlypearl-like sheenAdamantinebrilliant luster likethat of a diamondDull or Earthyluster of clay ordirtSatin spar Gypsum – Satiny lusterQuartz – Vitreous lusterThecolorof a mineral is determined byexamining a fresh surface in reflectedlight.Color istypically undiagnosticbecauseslight impurities can dramatically changethe color of a mineral (see quartz).Color may be helpful for minerals with ametallic luster and dark-colored mineralswith a non-metallic luster.

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Term
Fall
Professor
ScottWilkerson
Tags
Minerals

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