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.
Igneous Rocks
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
White Granite
Gray Granite
Red Granite
Pink Granite
Diorite
Gabbro
Igneous Rocks: Porphyry from two “stage cooling” with phenocryst
White Granite Porphry
White Granite Porphyry
Diorite Porphyry
Rhyolite Porphyry
Rhyolite Porphyry
Rhyolite Porphyry (Rare Llanite)
Andesite Porphyry (Albite)
Andesite Porphyry (Hornblende)
Gabbro Porphyry
Igneous Rocks: Aphanitic “without visible crystals” from cooling lavas
Rhyolite
Rhyolite
Andesite
Basalt
Basalt
Basalt with Olivine Xenolith
Igneous Rocks: Vesicular from gaseous cooling
Pumice
Pumice
Scoria
Scoria
Vesicular Rhyolite
Vesicular Rhyolite (with calcite)
Vesicular Basalt
Vesicular Basalt
Vesicular Basalt
Igneous Rocks: Glassy from rapid cooling
Obsidian
“Snowflake” Obsidian
Red Obsidian
Igneous Rocks: Pyroclastic
Tuff Breccia
Tuff Conglomerate
Ignimbrite
Igneous Rocks: Pegmatites
Feldspar Pegmatite
Tourmaline Pegmatite
Feldspar Pegmatite
Igneous Rocks: Ultra Mafic origins
Dunite
Peridotite
Basalt with Serpentine veins
Data: Pellant, Chris. Smithsonian Handbooks. Rocks and Minerals: The clearest recognition guide available. A Dorling Kindersley Book.