• Rock
• Values of rocks
• Solid mixture of crystal of one or more
minerals
• Human uses– Tools– Buildings– concrete
• Scientists– Earth & Space history– Fossil records
• Composition
• Texture
• The “ingredients” of a rock (what it is made of)
• Determined by the sizes, shapes & positions of the grains of which it is made
Rock OriginsRocks are classified by the way they formed.
Classifying Rocks
• Igneous Rock
• Origins
• Rock that forms when lava cools– Time it takes to cool &
solidify– Changes the rock
• MAGMA Solidifies like water freezing– Temperature range 700 C-
1250C– 3 ways to change magma
• Temperature• Pressure• Composition
Igneous Rocks
Igneous Rock Origins and TexturesThe texture of igneous rock varies according to its origin.
• Igneous Rock Formation
• Intrusive Igneous Rock
• Two types – inside and outside the earth
• When magma cools beneath the Earth’s surface.
• Usually coarse texture• Cools slowly• Named for size and way they intrude
– Plutons (balloon shape formations)– Batholiths– Sills
• Extrusive Igneous Rock
• Igneous rock that forms on the Earth’s surface
• Forms quickly• Very small crystals or none at all• i.e. lava flow becomes extrusive
igneous rock
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