Remember these rocks are formed under extreme heat and pressure. The original minerals within the rock recrystallize into larger sizes and the atoms become more tightly packed together, increasing the density of the rock. Non-foliated rock does not have planar patterns of strain. This rock often has a flaky plate-like appearance. Nonfoliated metamorphic rocks are formed around igneous intrusions where the temperatures are high but the pressures are relatively low and equal in all directions (confining pressure). The three metamorphic rocks listed below all form from a sedimentary rock called shale. fine grained foliated metamorphic rock Protolith shale or mudstone high clay from GEO 101 at Simmons College False, foliated rocks have tightly-pressed-together layers (or) nonfoliated rocks have no layers. Foliated Metamorphic Rocks: Some kinds of metamorphic rocks -- granite gneiss and biotite schist are two examples -- are strongly banded or foliated. The table below shows examples of common metamorphic rocks. These rocks do not have planar shapes of strain. Gneiss is a foliated metamorphic rock ,Is a common dispensed type of rock shaped by high-grade regional metamorphic approaches from pre-current formations that have been initially both igneous or sedimentary rocks Gneiss, metamorphic rock that has a awesome banding, which is apparent in hand specimen or on a microscopic scale. When shale is metamorphosed to different grades it forms different types of foliated metamorphic rocks. Schist: Schists are foliated metamorphic rocks of medium to coarse texture. Thus, regional metamorphism usually results in forming metamorphic rocks that are strongly foliated, such as slates, schists, and gniesses. Slate, schist and gneiss are examples of foliated metamorphic rocks. Non-foliated rock does not have planar patterns of strain. • Non-foliated metamorphic rocks appear massive or granular without the characteristic parallel mineral grains in foliated rocks. Metamorphic Rock # 2. Non-foliated rocks occur when the temperatures are high but the pressure is low or equalized on both sides. The differential stress usually results from tectonic forces that produce compressional stresses in the rocks, such as when two continental masses collide. Metamorphic rocks are catagorized into two main types: foliated and non-foliated. Three examples of foliated metamorphic rocks are gniess, slate and schist. (Foliated means the parallel arrangement of certain mineral grains that gives the rock a striped appearance.) Some examples of foliated metamorphic rock are slate and gneiss. Non-foliated metamorphic rocks are rocks that have been changed by heat and pressure into rocks with a non-layered or banded appearance. They are recognized by their strong foliation and ease of parting. Suppose while hauling rocks, you accidentally drop one. Rocks that were subjected to uniform pressure from all sides, or those that lack minerals with distinctive growth habits, will not be foliated. Clicking on the name of the rock will bring up a larger picture and a description of the rock type in a new window. • Non-foliated metamorphic rocks are classified based primarily on their composition. Some examples of non-foliated metamorphic rocks include quartzite, marble, amphibolite and hornfels. Nonfoliated rocks have very narrow layering. Shale is made from mud and clay in places like seafloors and swamps. Foliated rocks occur as a result of increased strain that distorts the shape of the rock in a single plane. The mineral grains are generally large enough to be seen with the naked eye. Learn more about metamorphic rocks here. For example, slate is a foliated metamorphic rock, originating from shale. It breaks apart in flat, planar sections. • Marble, quartzite, and soapstone are examples of non-foliated metamorphic rocks.