MineralRatingTesting Method Talc1Softest known mineral. It flakes easily when scratched by a fingernail. Gypsum2A fingernail can easily scratch it. Calcite3A.

Presentación del tema: "MineralRatingTesting Method Talc1Softest known mineral. It flakes easily when scratched by a fingernail. Gypsum2A fingernail can easily scratch it. Calcite3A."— Transcripción de la presentación:

1 MineralRatingTesting Method Talc1Softest known mineral. It flakes easily when scratched by a fingernail. Gypsum2A fingernail can easily scratch it. Calcite3A fingernail cannot scratch it, but a copper penny can. Fluorite4A steel knife can easily scratch it. Apatite5A steel knife can scratch it. Feldspar6Cannot be scratched by a steel knife, but it can scratch window glass. Quartz7Can scratch steel and hard glass easily. Topaz8Can scratch quartz. Corundum9Can scratch topaz. Diamond10Hardest known mineral. Diamond can scratch all other substances. Internet Activity Mineral Formation Mohs Hardness Scale

2 Mineral Formation Many minerals form at chimneys along Earth's mid-ocean ridge. Chimneys occur in areas where sea-floor spreading causes cracks in the oceanic crust. The mineral formation process begins when ocean water seeps through cracks in the crust. What happens next? Use the illustration to put the steps below in their correct order. Enter the numbers 1–4 in the space next to each step. _____ The heated water dissolves minerals in the crust. _____ Minerals crystallize in the cold ocean water and settle to the ocean floor. _____ Magma heats the water that has seeped into the cracks. _____ The hot mineral solution billows out of chimneys.

3

4 Rocks

5 Rock Identification How would you identify the rocks above? Scientists identify rocks by observing three rock characteristics: texture, composition, and origin. Most rocks are made up of particles of minerals or other rocks, called grains. These grains give a rock's surface its look and feel, or texture. The composition of a rock describes the minerals or rocks that combine to form a rock. The origin of a rock describes how a rock forms. Rocks formed from the cooling of molten rock are called igneous rocks. Sedimentary rock forms when particles of other rocks, plants, or animals are pressed and cemented together. Metamorphic rock is formed when an existing rock is changed by heat, pressure, or chemical reactions. Examine the Rock Characteristics chart below to learn about six common types of rock.

6 Rock Characteristics Next, print and complete the Rock Identification Table. Click on each rock picture to view a photograph showing an example of each rock. In the table, write down information about the texture, composition, and origin of the pictured rock. Use your description of each rock and the Rock Characteristics chart to identify the pictured rock.

7 Rock NameComposition QuartzMicaFeldsparHornblendeGlass GneissXXXX GraniteXXXX Obsidian X Pumice X QuartziteX X SandstoneX X Rock Name TextureOrigin Coarse Grain Fine Grain No Grain Banded Grain IgneousSedime ntary Metam orphic Gneiss X X GraniteX X Obsidia n X X PumiceX X Quartzi te X X Sandsto ne X X Rock Identification Table

8