Properties of MineralsProperties of MineralsEarth’s SurfaceEarth’s Surface2.2 (pg. 51-57)2.2 (pg. 51-57)

Ms. Wells, ScienceMs. Wells, Science

Properties of Minerals:Properties of Minerals:Why do we care?Why do we care?

• Property – characteristic, quality or trait of Property – characteristic, quality or trait of somethingsomething

• Used to IDENTIFY a mineralUsed to IDENTIFY a mineral

• Is it salt? Is it quartz? Is it talc? Who Is it salt? Is it quartz? Is it talc? Who knows! TEST the knows! TEST the propertiesproperties to find out! to find out!

Properties of Minerals:Properties of Minerals:Which are the most important?Which are the most important?

• StreakStreak• LusterLuster• Cleavage or FractureCleavage or Fracture• DensityDensity• HardnessHardness

Appearance Property: StreakAppearance Property: Streak

• StreakStreak – – color of the color of the powderpowder a mineral a mineral leaves behind when leaves behind when you scrape it across you scrape it across somethingsomething

• Shows Shows true colortrue color better than looking at a better than looking at a whole mineralwhole mineral

• Use “streak plate” Use “streak plate” made of porcelainmade of porcelain

Appearance Properties: LusterAppearance Properties: Luster

• LusterLuster – the way a mineral reflects light – the way a mineral reflects light• (QUALITATIVE OBSERVATION (QUALITATIVE OBSERVATION ))

• Luster Terms:Luster Terms:• Metallic – shiny like a metalMetallic – shiny like a metal

• NonNonmetallic – metallic – notnot shiny like metal shiny like metal• Oily – feels or looks greasyOily – feels or looks greasy• Glassy – shiny like glassGlassy – shiny like glass• Dull – plain, earthy Dull – plain, earthy

Metallic LusterMetallic Luster

Nonmetallic LusterNonmetallic Luster

Breaking Properties:Breaking Properties:Cleavage or FractureCleavage or Fracture

• CleavageCleavage – mineral – mineral breaks along a flat breaks along a flat surface or into sheetssurface or into sheets

• FractureFracture – when a – when a mineral breaks with mineral breaks with lots of jagged edgeslots of jagged edges

Property: DensityProperty: Density

• DensityDensity – – massmass divided by divided by volumevolume of a of a mineral (in other mineral (in other words: how heavy it is words: how heavy it is for how much space it for how much space it takes up)takes up)

• GOLD is denser than GOLD is denser than PYRITE (“Fool’s Gold”)PYRITE (“Fool’s Gold”)• Feels heavierFeels heavier

Fracture or Cleavage?Fracture or Cleavage?

• Determined by the Determined by the crystal structurecrystal structure of the of the mineralmineral• Crystal structureCrystal structure – how – how

atoms of the mineral atoms of the mineral are arranged (special are arranged (special order of the atoms)order of the atoms)

• ALL minerals have ALL minerals have crystal structure, but crystal structure, but there are different there are different kindskinds

Property: HardnessProperty: Hardness

• HardnessHardness – a mineral’s resistance to being – a mineral’s resistance to being scratched scratched

• test what can scratch it and what it can test what can scratch it and what it can scratchscratch

• Use “Moh’s Scale” to assign hardnessUse “Moh’s Scale” to assign hardness• Scale of 1 to 10Scale of 1 to 10

• 10 = hardest = diamond!10 = hardest = diamond!• 1 = softest = talc!1 = softest = talc!

Extra Special Properties Extra Special Properties

1. Fluorescence1. Fluorescence• Fluorescent color under ultraviolet (UV) lightFluorescent color under ultraviolet (UV) light

2. Magnetic2. Magnetic• Attract magnetsAttract magnets

3. Acid reaction3. Acid reaction• Carbon dioxide gas bubbles off when you drop Carbon dioxide gas bubbles off when you drop

acid on themacid on them• Carbonates!Carbonates!

FluorescenceFluorescence

MagneticMagnetic

Carbonate Acid ReactionCarbonate Acid Reaction

The End!The End!YAY!YAY!