The Earth is made of rocks and this poster provides a
comprehensive overview of what they are and how they are
formed. It begins by explaining that rocks are made of
minerals and that each type of rock is the result of a
specific mixture of minerals subjected to a clearly defined
geological process. The bulk of the poster is divided into
three sections, one for each type of rock: igneous, sedimentary
and metamorphic. An illustration shows how they are made.
It is followed by photographs of a dozen representational
specimens. A dramatic photograph shows a natural formation.
A bonus section shows and explains some of the more specialized
and popular rock forms such as geodes, concretions, agates and
thunder balls. This is a great poster for earth science classes,
but one also appreciated by rock collectors as it is a helpful
resource for identification.
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