What is the difference between rock and mineral?
You’ve got at least 4 different questions there. On the first one, Ami’s answer is almost correct – my only objection would be that rocks are composed of one or more minerals. Any geological dictionary or school text book will give you an adequate defintion of a rock and of a mineral to allow you to generally distinguish between them. Geology is probably the least exact of all the sciences, so there’s always exceptions. Most rocks do indeed contain more than one mineral. For example, think of granite (a common intrusive igneous rock containing the minerals quartz, feldspar, hornblende, amphibole, mica, etc.) or basalt (a common volcanic rock containing plagioclase, pyroxene, olivine, magnetite, and maybe some apatite). However, there are many kinds of rocks that consist of essentially of only one mineral, such as anorthosite (plagioclase), limestone (calcite), and sandstone (quartz). Some minerals can also be a rock, such as gypsum, obsidian, or dolomite. The size of the sample or the
