Name:

Igneous Rocks Scaffold

A rock is an _________________________ of one or more _______________________.

An igneous rock forms from the cooling and ______________________ of liquid rock.

Texture of Igneous Rock

  1. Phaneritic
    • ______________________ Rocks - ______________________ cool beneath the Earth's surface.
    • ______________________ crystals or grains visible with the naked eye
    • Examples: ____________________________________________.
  2. Aphanitic
    • ______________________ Rocks - form at the Earth's ______________________ and cool ______________________.
    • ______________________ crystals or grains not visible with the naked eye
    • The rock is glassy or the crystals are small.
    • These are the rocks and ash of volcanoes.
    • Examples: ____________________________________________.
  3. Porphyritic
    • ______________________ crystals surrounded with a ______________________ grained or glassy matrix.
    • Formed when partially cooled intrusive rock is ______________________ to the surface and cools rapidly.
    • Many rhyolites are porphyritic.

Composition of Igneous Rock

  1. ______________________ rocks (basaltic)
    • ______________________ rocks and minerals rich in magnesium and iron (ferric).
    • Some ______________________ minerals present.
    • Mafic minerals ______________________ at higher temperatures than felsic minerals.
    • ______________________dense: ≈ 2.6 g/cm3
    • Examples: ____________________________________________.
  2. ______________________ rocks (andesitic)
    • Mineral makeup ______________________ mafic and felsic.
    • Examples: diorite and andesite.
  3. ______________________ rocks (granitic)
    • ______________________ colored rocks and minerals rich in feldspar and silica.
    • ______________________ dense: ≈ 2.3 g/cm3
    • Examples: granite and rhyolite.