Gneiss and schist very similar rocks. What are the major diffarences ?
Gneiss and schist are both types of metamorphic rocks, which means they are rocks that have undergone significant changes in texture, composition, and/or structure due to intense heat and pressure without melting.
The main difference between gneiss and schist is their texture and mineral composition. Gneiss typically has a banded appearance, with alternating light and dark layers, due to the segregation of different minerals during the metamorphic process. Schist, on the other hand, has a more layered or foliated appearance, with the minerals aligned in parallel planes.
Gneiss is typically composed of minerals such as quartz, feldspar, and mica, and can be formed from various parent rocks such as granite or shale. Schist is typically composed of minerals such as mica, chlorite, and talc, and is commonly formed from shale or other fine-grained sedimentary rocks.
Another difference between gneiss and schist is their relative hardness. Gneiss is generally harder and more resistant to erosion than schist due to its coarser mineral grains and stronger bonds between them.
In summary, the main differences between gneiss and schist are their texture, mineral composition, and relative hardness. Gneiss has a banded appearance with coarser mineral grains, while schist has a layered appearance with finer mineral grains.