Minerals, Rocks and Fossils S6E5 b. Investigate the contribution of minerals to rock composition. g. Describe how fossils show evidence of the changing surface and climate of the Earth.
What is a mineral? Naturally occurring Non-organic Characteristic chemical composition Distinctive physical properties Crystalline structure
Mineral properties Color Luster Habit (Shape) Cleavage & Fracture Streak Hardness
Color: Not mineral specific
Luster: How minerals reflect light Metallic Non-metallic
Mineral Habit (Shape) Shape a mineral takes if grown unimpeded Mineral Java Applet
Cleavage & Fracture Cleavage: planes of weakness along which minerals can break (smooth and flat) Fracture: surfaces along which minerals can break (ragged)
Cleavage & Fracture Best identified on a fracture surface
Streak: The powdered form of a mineral
Based on Moh’s scale of hardness
Other Properties Specific gravity (weight) Reaction to acid Striations (number of scratches or parallel grooves on the surface of a rock) Magnetism
Classifying Rocks Rocks are classified by how they formed and what they’re made of There are 3 general classes of rocks Igneous Rocks…are formed when lava and magma crystallize to form solid rock Metamorphic Rocks…are formed when an existing rock is partially melted, squeezed, or both Sedimentary Rocks…are formed when sediments (sand clay, and silt) are compressed and become solid rock
Igneous Rocks
Metamorphic Rocks Schist Gneiss
Sedimentary Rocks Shale Conglomerate Sandstone
Fossils The remains or imprints of living things of the past found in Sedimentary rocks.
Fossils provide information about life and conditions in the past.
Fossils of Sea Creatures Oceans once covered the area
Fossils of Plants Plant fossils can tell us about the ancient environment
Animal Fossils Animal fossils can tell us About past environments What the animal ate How they lived
Vocabulary Quiz on Monday Next class… We’ll take a closer look at the different types of rocks and determine the minerals that make them up. Vocabulary Quiz on Monday