Methylphenidate is a commonly prescribed psychostimulant and works by increasing the activity of the central nervous system. It produces such effects as increasing or maintaining alertness, combating fatigue, and improving attention. The short-term benefits and cost effectiveness of methylphenidate are well established.
(image copied from here). 1  Igneous Rocks: form by crystallizing melted material (magma). 2  They can form either on the surface (extrusive igneous rocks), or deep in the crust (intrusive or plutonic igneous rocks).
Igneous Rocks are formed by the cooling and crystallization of a silicate melt (dominated by oxygen and silicon, with a variety of other metals). The occurrence and distribution of igneous rocks and igneous rocks types can be related to the operation of plate tectonics. The molten rock material from which igneous rocks form is called magma.