Minerals, Rocks and Fossils

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 Other

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 Fracture: surfaces along which minerals can break

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 Reaction to acid Striations 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 What part of the ocean

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