Presentation on theme: "Properties of Minerals"— Presentation transcript:
1 Properties of Minerals Geologists use characteristics to tell one mineral from another
2 What 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:
3 Mineral Properties we will mainly study: LusterHardnessStreakCleavage
4 Special Properties Fluorescence Optical Properties: double refraction TasteConductivityReaction to AcidMagnetismDensityVideo:Song:
5 LusterRefers 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.
8 Hardness Is measured by how easy it is to scratch. Geologists use Mohs Hardness Scale
9 Gypsum is soft, it can be scratched by a fingernail.
10 Calcite is soft, but a little harder because it cannot be scratched by a fingernail, but it can be scratched by a penny.
11 Fluorite is harder. It can be scratched by a nail, but not a penny or fingernail.
12 Diamonds are the hardest mineral, so it scratches every mineral.
13 Cleavage 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.
14 Mica has cleavage in one direction. It breaks along one line.
15 Feldspar has two lines of cleavage. It breaks along two lines.
16 StreakRed 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.
17 GoldWhen gold is run across a streak plate it makes a yellowish-gold color.That makes sense.
18 Pyrite 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.
19 Hematite 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.