Quartz Quartz is hexagonal and commonly occurs as crystals ranging in size form microscopic to crystals weighing several tons. Where it crystallizes unhindered by other crystals, such as in cavities in rock or in a liquid containing few other crystals, it shows well-developed hexagonal prisms and sometimes showing apparent hexagonal pyramids or dipyramid. When it crystallizes in an environment where growth is inhibited by the surroundings, it rarely show crystal faces. It is also found as microcrystalline masses, such as in the rock chert, and as fibrous masses, such as in chalcedony. Vitreous lusture. As visible crystals, Quartz is one of the more common rock forming minerals. It occurs in siliceous igneous rocks such as volcanic rhyolite and plutonic granitic rocks. It is common in metamorphic rocks at all grades of metamorphism, and is the chief constituent of sand. Because it is highly resistant to chemical weathering, it is found in a wide varie...
TYPES OF METAMORPHISM Metamorphism can take place in several environments where special conditions exist like pressure, temperature, stress, conditions, or chemical environments.by this different conditions application several different types of metamorphism are :- Contact metamorphism Burial metamorphism Dynamic metamorphism Regional metamorphism Hydrothermal metamorphism Subduction related metamorphism Shock metamorphism Contact Metamorphism ( alias thermal metamorphism) - Figure 1.1 Occurs adjacent to igneous intrusions and results from high temperatures associated with the igneous intrusion. Since only a ...