Classification of Rocks

Conglomerate (Nagelfluh)

- Sedimentary Rock → clastic

- formed from the cementing of different pebble (Geröll, Kieselstein) sized rock fragments

- formed by river movement or ocean wave action

Sandstone

- sedimentary rock → clastic

- forms from cementation of sand sized grains (mainly quartz, SiO2) forming solid rock

Limestone (light; dark ones exist too)

- sedimentary rock → chemical

- produced from CaCO3 and sediments, most often formed in oceans

- mainly made from CaCO3 which percipitate in ocean water or from sea creatures (algae or coral)

- Chalk is a type of limestone

Granite

- igneous rock → intrusive

- forms as magma cools far under the earth's surface

- hardens deep underground -> cools slowly, becomes very hard

- composed of three minerals -> feldspar, quartz and mica (Glimmer)

Basalt

- igneous rock → extrusive

- dark coloured

- fine-grained

- most often formed by the rapid cooling of lava

- most common of all igneous rocks

Gneiss

- metamorphic rock → foliated

- high-grade metamorphic rock

- subjected to a lot of heat and pressure

- minerals are the same as in granite

- formed by metamorphism of the igneous rock granite

Marble

- metamorphic rock → non-foliated

- metamorphed limestone

- large concentration of Calcium Carbonate

- many colour variances due to impurities present at formation

- much harder than limestone

- acid disolves marbel (use acid-free cleaner for marbel baths)

Obsidian

- igneous rock → extrusive

- glasslike

- of volcanic origin

- formed when lava cools down so quickly by exposure to water or air that no crystals can form

- stone age people used it for arrowheads, knives, spearheads and other cutting tools

Pumice

- deutsch: Bimstein

- igneous rock → extrusive

- light coloured

- lots of air bubbles

- formed when lava is ejected ans shot through the air during an eruption, cools mid flight, gases escape, leaving a rock full of holes

- floats on water

Serpentinite

- metamorphic rock → foliated

Clay

- sedimentary rock → clastic

- consists of sand-like grains, but they are way smaller than sand

Sedimentary Rocks

- formed by compaction and/or cementation

Clastic (Trümmergestein)

• Conglomerate

• Sandstone

• Clay

Chemical

• Limestone

Biologic

• Coal

Metamorphic Rocks

- formed by heat and/or preassure (metamorphism)

Foliated (different Layers)

• Gneiss

• Serpentinite

Non-foliated

• Marble

Igneous Rocks

- formed by solidification of molten rocks (MAGMA)

Intrusive

• Granite (becomes Gneiss under pressure)

Extrusive (Vulkanite)

• Basalt

• Obsidian

• Pumice

Coal

- sedimentary rock → biologic

- organic sedimentary rock

- forms from the build up and decay of plant and animal material, usually in swamp regions with an abundant supply of growing vegetation and low amounts of oxygen

- new layers of vegetation build quickly and bury the dead and decaying layer

- bacteria have little time to decompose the vegetation because of the little oxygen

- compressed vegetation → coal

- Peat (Torf) -> first stage of coal formation

- lignite (Braunkohle) ->Stage 2

- Bituminous -> Stage 3

- Anthractie -> Stage 4