Geology And Geophysics

How Rocks and Minerals Differ

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"How Rocks and Minerals Differ"
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Rocks and minerals, minerals and rocks.  What are they, how do they differ, and how are they used?  Common questions easily found on various websites with some simple answers.  Lets answer them one at a time.

Definitions first!  An excellent website for defining minerals and rocks is Minerals Resources and will tell you that a mineral is "A mineral, by definition, is any naturally occurring, inorganic substance, often additionally characterized by an exact crystal structure Its chemical structure can be exact, or can vary within limits. Elements that occur naturally are also considered minerals."  The same website defines a rock as "The best way to define a rock is to say that it is an indefinite mixture of naturally occurring substances, mainly minerals. Its composition may vary in containment of minerals and organic substances, and are never exact. They can range from tiny microscopic grains of minerals or organic substances to coarse agglomerates of different minerals, where the individual minerals are easily discernible. They may range in size from tiny pebbles to huge mountains."

Using these two definitions, it is easy to see the differences.  Minerals are uniform and "pure" while rocks are mixtures and contain many different minerals.  There are over 3000 types of minerals, and 3 basic types of rock (Igneous, sedimentary and metamorphic).  Rocks form mountains, land and the earth's crust, minerals are extracted from rocks.  All rocks are composed of minerals, but minerals are not just rocks!

How are they used?  Rocks have been used for thousands of years by man as building materials.  We started life by living in caves, which are made of rock, and then in many civilization continued by building structures with rocks.  Look at the pyramids of Egypt and South America, the Great Wall of China or Stonehenge.  All are made of rock, rock lasts!  Minerals are extracted from rocks and used for creating things, but more specific than just building.  Silica is made into glass, metals into wires, and so on.  The more precious minerals are used for creating jewelry!  Gold, silver, diamonds, emeralds and rubies are all minerals!

A summary of an overview of rocks and minerals?  Rock are the conglomerates from which minerals are extracted while minerals are more pure compounds or crystals.  Rocks and stones are used primarily for building (or carving for statues) while minerals are more specific, mostly known for use in jewelry!

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