IGNEOUS ROCK SPECIMEN
Rocks are simply defined as an aggregate of minerals. There three classifications Igneous Rocks formed from cooled lava and magma associated with volcanic activity. Sedimentary Rocks formed from compacting sediments (pebbles, sand and clay) often below sea level. Metamorphic Rocks forms from preexisting rocks that get buried and remain in a solid state while immersed at various levels of heat and pressure.
It is essentially a silicate melt and may contain, as well as silicon and oxygen, other elements, particularly aluminum, iron, calcium, sodium, potassium and magnesium. These combine, as the magma or lava crystallizes, to form silicate minerals, which in combination make up igneous rocks.
Igneous Rocks: Phaneritic “visible crystals” from cooling magmas
Igneous Rocks: Porphyry from two “stage cooling” with phenocryst
White Granite Porphry
White Granite Porphyry
Rhyolite Porphyry (Rare Llanite)
Andesite Porphyry (Albite)
Andesite Porphyry (Hornblende)
Igneous Rocks: Aphanitic “without visible crystals” from cooling lavas
Basalt with Olivine Xenolith
Igneous Rocks: Vesicular from gaseous cooling
Vesicular Rhyolite (with calcite)
Igneous Rocks: Glassy from rapid cooling
Igneous Rocks: Pyroclastic
Igneous Rocks: Pegmatites
Igneous Rocks: Ultra Mafic origins
Basalt with Serpentine veins
Data: Pellant, Chris. Smithsonian Handbooks. Rocks and Minerals: The clearest recognition guide available. A Dorling Kindersley Book.