What is the differences between igneous, metamorphic and sedimentary rocks. give some photos?
Igneous rocks are those that have formed from cooling magma. Most are made up of closely interlocking crystals, sometimes too small to see with the Mk1 eyeball (like a basalt) but often with visible crystals ( like a granite or pegmatite). The exception to those made up of crystals are the products of explosive volcanic events which tend to be glassy or ash like. These pyroclastic rocks can sometimes look like sedimentary rocks as the ash behaves much like other sediments. Metamorphic rocks are rocks that started off as something else, but were changed by heat and pressure. The appearance can be quite variable. Marble and quartzite are made up of pretty much single minerals (calcite and quartz respectively) but many metamorphic rocks are recognisable by their texture (Gneiss or Schists) with contorted layers of crystals Sedimentary rocks are made up of particles (grains) of broken down other rocks. These grains may be very fine (e. g. mudstone or shale) a little coarser (e.g. sandstone
