Geology & Soils

Igneous Rock: Diorite

Diorite

Diorite is a coarse grained igneous rock composed of plagioclase feldspar, amphibole, and pyroxine minerals. It generally also contains small amounts of biotite mica and a very small amount of quartz. It has a "salt and pepper" appearance, with white and dark minerals. Its cleavage faces intersect at oblique angles.


Metamorphic Rock: Quartzite

Quartzite

Quartzite is a metamorphic rock derived from sandstone. It is coarse grained and very hard. Heat and pressure on sandstone fuse grains of quartz sand in order to make quartzite. Quartzite is usually white or grey, but it can have a red or pink coloring if iron oxides are present in the sample, such as in the example quartzite to the left.




Sedimentary Rock: Siltstone


Siltstone is a sedimentary rock made from silt. Silt is another name for clay. It is very finely grained. Siltstone looks a lot like sandstone, except the grain of siltstone is finer than that of sandstone. Silica, calcite, and iron oxides are the minerals most commonly found in siltstone.



Soil Types:
The 12 soil types can be found here. Scientists classify soils based on the particle size and the texture of the soil. They classify soils based on the percent clay, percent silt, and percent sand found in the soil sample.