Rocks Natural Science

3 Types of Rocks (1) Igneous – results from the cooling and solidification of hot fluid materials (magma) Magma – molten rock and minerals below the earth’s surface Lava – Magma that has reached the earth’s surface

Cont. (2) Sedimentary Rock – Rocks made up of fragments of other rocks and minerals –Usually seen around lakes, oceans, and low lying areas –These are products of erosion

Cont. (3) Metamorphic Rock – these are sedimentary or igneous rocks whose minerals and texture have been changed by pressure and high temperatures. (but DID NOT melt) –Usually occurs deep within the earth’s crust

Igneous Extrusive - refers to the cooling and hardening of lava on the earth’s surface Rapid cooling Produces glassy rock (obsidian) or gas bubbles in rock (pumice ) Slow cooling Produces rocks with a clear crystalline structure Intrusive - refers to the slow cooling and solidification below the earth’s surface Produces much larger crystals

Sedimentary Rock Made up of fragments of other rocks and minerals Are the products of erosion The high cuts in our area show sedimentary rock layers Two classifications of sedimentary rock Clastic – broken rock fragments and dead organisms accumulate over time and become compacted together Chemical sedimentary rock – formed from chemical precipitation Crystalline ions attract forming larger rock fragments composed of minerals Limestone and sandstone in our area are examples of this

Metamorphic Sedimentary or igneous rocks - minerals and texture have been changed by high temperatures and pressure, but did not melt Usually occurs deep within the earth’s crust Gnesis and Schist Gnesis Schist

Minerals Naturally occurring non-organic substance with a definite crystalline structure Mineral properties Color Luster – describes how light is reflected of its surface (metallic vs. non-metallic) Shape Cleavage – planes of weakness along which a mineral can break Fracture – surfaces along which a mineral can break Hardness – based on Moh’s scale of hardness which is 1=10 Examples of hardness 2 fingernail 5 glass 9-10 diamond

Rock Cycle