Download IGNEOUS ROCKS – Classified according to their origin, texture, and

IGNEOUS ROCKS – Classified according to their origin, texture, and composition
Origin
Where do they form? (Define each and give 1 example of each
Drawing
Extrusive rock
Ex: Basalt—most common extrusive rock & most
common rocks on Earth
Forms much of Earth’s ocean floor
Intrusive rock
Ex: Granite—most abundant intrusive rock on
Earth’s continents
Forms the core of many mountain ranges
Texture
How do they form and what sizes of crystals form?
Fine - Grained
Ex: Basalt (Glassy texture, crystals too small to be
seen with a microscope)
Ex: Obsidian (Smooth, shiny texture like thick glass;
Cooled without forming crystals)
Course - Grained
Ex. Granite (Crystals vary in size and color)
Ex. Porphyry (Looks like gelatin with chopped fruit
mixed in)
Crystal Size Drawing
Mineral Composition
Most of Earth’s minerals contain silica, a material formed from
oxygen & silicon.
What happens when
rocks are high in silica?
Ex: Granite
What happens when
rocks are low in silica?
Uses
Ex: Basalt
List at least 6 things that igneous rocks have/can be used for.
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