IGNEOUS ROCKS Classified According to Their Origin, Texture, and Composition

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? / Crystal Size Drawing
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)
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? / Ex: Basalt
Uses / List at least 6 things that igneous rocks have/can be used for.
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