Page 105 - SST Class 07
P. 105

The properties of these rocks depend on the             metamorphic rocks. A metal can be pressed into
            materials they are made of. These materials are         wires and sheets. Some important metals are iron,
            called minerals. A rock may have one or more            gold, silver, lead, copper, zinc etc.
            minerals. Minerals are present in rocks naturally
                                                                     Non-metallic Minerals
            and   can   be   identified  with   their  physical
            properties and chemical composition. We get             These   minerals    are  chiefly  associated   with
            metals or chemicals from minerals. A mineral has        sedimentary rocks, such as clay, sulphur, coal,
            two or three simple substances called elements     .    petroleum, salt etc.
            The rock which has a large amount of a mineral is       The modern progress and development could not
            called an ore . Such rocks are mined for procuring      have   been    achieved    without    minerals,   so
            that mineral.                                           important they are to us.

            Minerals are of great economic value. Their
            importance can be gauged from the fact that             Activity
            different ages in the history of man have been           Name any four metals that are used in your
            named after minerals : Iron Age, Copper Age,             house :
            Bronze Age.
                                                                     (a)  __________________________________
            We    can   classify  minerals   into  two    broad      (b)  __________________________________
            types—metallic  and non-metallic .
                                                                     (c)  __________________________________
            Metallic Minerals
                                                                     (d)  __________________________________
            Metallic minerals are found in igneous and






            v The earth is made up of three main layers—crust, mantle and core.
            v The crust is the outermost covering and is made up of SIAL and SIMA.

            v The core is the innermost layer of the earth.
            v The inner core is solid while the outer core is in molten state.
            v Rock is the material that forms the crust of the earth.
            v Rocks are of three types—igneous, sedimentary and metamorphic.
            v Rocks undergo a change, this process is called rock cycle.

            v We get minerals from the rocks which are of great economical value.







            A.   Tick (3) the right option :

                 1.   ______________    is the most important layer as it sustains life.
                      (a) core                         (b) crust                       (c) mantle
                 2.   The oceanic crust is made up of ______________  .
                      (a) SIMA                         (b) SIAL                        (c) NIFE
                 3.  The layer just below the crust is called ______________ .
                      (a) core                         (b) mantle                      (c) magma

                                                                                                 Inside the Earth
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