http://itc.gsw.edu/faculty/tweiland/igrx1a.htm WebAndesite is the name of a family of fine-grained, extrusive igneous rocks that are usually light to dark gray in color. They have a mineral composition that is intermediate between granite and basalt. Andesite is a rock …

Physical Geology Lab Samples - Georgia Southwestern State …

WebWith the passage of time, some obsidian begins to crystallize. This process does not happen at a uniform rate throughout the rock. Instead it begins at various locations within the rock. ... Most obsidians have a composition … WebRhyolite: 65-75 SiO 2 %, low in Fe, Mg, Ca, high in K, Na. 650 - 800 o C: 10 5 - 10 9 PaS: High: Textures of Igneous Rocks. The main factor that determines the texture of an igneous rock is the cooling rate (dT/dt) Other factors involved are: The diffusion rate - the rate at which atoms or molecules can move (diffuse) through the liquid. ... how to install a roll up garage door youtube

Obsidian Rock, Color, Composition, & Uses Britannica

WebCooling the mothballs and crayon mixture. Before the demonstration: Fill one beaker with 100 mL of water and place it on the hot plate; bring to a boil. Crush one of the mothballs with the pliers and place it into a test … WebNote that a granite is the coarse grained equivalent of a rhyolite. That is, if the rate of cooling is very slow a granite will form. The same melt, cooled rapidly, will form a … how to install a roof drain