The top layer of soil. Plant and other organic debris builds up in this layer. This is the part of the soil generally referred to as 'top soil'. A fan-shaped pile of sediment that forms where a rapidly flowing mountain stream enters a relatively flat valley. Amphibole minerals generally contain iron, magnesium, calcium and aluminum in varying amounts, along with water.
Blue amphibole contains sodium and, of course, is bluish in color.
Although the name amphibolite usually refers to a type of metamorphic rock, an igneous rock composed dominantly of amphibole can be called an amphibolite too. Commonly with visible crystals of plagioclase feldspar. Generally occurs in lava flows, but also as dikes. The most common rock in volcanic arcs. Refers to minerals or other materials which do not have water as an primary constituent.