Presentation on theme: "Properties of Minerals"— Presentation transcript:
1Properties of Minerals Geologists use characteristics to tell one mineral from another
2What is a Mineral? Must be a solid. Must occur in nature. Must have a definable chemical composition (NaCl).Must have a crystalline structure.Must be inorganic.Video:
3Mineral Properties we will mainly study: LusterHardnessStreakCleavage
4Special Properties Fluorescence Optical Properties: double refraction TasteConductivityReaction to AcidMagnetismDensityVideo:Song:
5LusterRefers to the way light reflects from the surface of the mineral.There are two types of luster,Metallic: looks like polished metal.Nonmetallic: does not look like polished metal.Nonmetallic can be shiny or dull.
8Hardness Is measured by how easy it is to scratch. Geologists use Mohs Hardness Scale
9Gypsum is soft, it can be scratched by a fingernail.
10Calcite is soft, but a little harder because it cannot be scratched by a fingernail, but it can be scratched by a penny.
11Fluorite is harder. It can be scratched by a nail, but not a penny or fingernail.
12Diamonds are the hardest mineral, so it scratches every mineral.
13Cleavage Not all minerals have cleavage. Some minerals split easily along a flat surface.The number of lines that are created when a mineral is split will be the number of cleavage lines.
14Mica has cleavage in one direction. It breaks along one line.
15Feldspar has two lines of cleavage. It breaks along two lines.
16StreakRed chalk on a chalk board makes red marks. White chalk makes white marks.Not all minerals work this way. When some minerals are scratched along a ceramic streak plate, it creates a different color.
17GoldWhen gold is run across a streak plate it makes a yellowish-gold color.That makes sense.
18Pyrite or “Fool’s Gold” When pyrite is run across a streak plate, it has a black or dark green streak.Pyrite is not worth much money, while gold is worth a lot. They look alike, so miners call it fool’s gold.
19Hematite Hematite’s color is grey, but its streak is red. Hema means blood.The mineral was named hematite because it looked like it was bleeding when it was taken across a streak plate.