Medium-grained rocks can be composed of quartz grains, feldspar grains (arkose), or rock fragments and clay (graywacke). Sandstone (Photograph by Parvinder Sethi). Medium-sized grains in clastic sedimentary rocks form sandstone. This sample is a quartz sandstone.
Bliss â¢ McCabe: Discourse Genres 135 special interests and can give lengthy descriptions ofrelevant objects such as rocks or music).â¢ We have identified the following components thatappear to be necessary for a complete proceduraldiscourse regarding how a game is played: goals,players, materials, and procedures.
However, in order to maintain the high level of discourse weâve all come to value and expect, please keep the following criteria in mind: 1  Enrich the conversation. 2  Stay focused and on track. 3  Be respectful.  Use standard writing 1  style. NOTE: Spam and/or promotional messages and links within a comment will be removed.