MATTER AND MINERALS 1.An atom is the smallest part of an
element that retains the elements' properties. 2.Compounds are
substances that are made up of two or more elements that are
chemically bonded as molecules. 3.Minerals are solids and are
composed of elements.
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WHAT DO MINERALS HAVE IN COMMON? A mineral is a naturally
occurring, inorganic solid that has a definite crystalline
structure and chemical composition. Minerals are grouped according
to the shape of their chystals.
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EXAMPLES OF MINERALS THE MINERAL AMETHYST- Chemical FormulaSiO
2 Composition :Silicon dioxide. Its purple coloring is usually
caused by impurities of iron or manganese compounds. ColorLight to
dark purple. Sometimes banded with purple and whitish lines. May
also be mixed together with Citrine. StreakWhite Hardness7
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INORGANIC AND NATURALLY OCCURRING AN inorganic substance is not
made up of living things or the remains of living things. Minerals
are formed by many different natural processes that occur on Earth
and throughout the universe. Talc used in baby powered: is formed
deep in Earth as high temperature and pressure change the
rock.
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CRYSTALLINE STRUCTURE Minerals are composed of crystals : A
crystal is a sold, geometric form that results from a repeating
patter of atoms or molecules. Turn to page 142 and 143 in
textbook.
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CRYSTALS SHAPE A crystals shape is produced by the arrangement
of the atoms or the molecules within the crystal. The arrangement
is determined by the kinds of atoms or molecules that make up the
mineral.
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MINERALS CAN FORM THREE WAYS 1. Magma and lava cooling
2.Metamorphism 3. From Solutions
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MINERALS FORMED FROM MAGMA OR LAVE Magma and lava contains
atoms present in minerals, when magma and lava cool quickly and
solidify small crystals form. When cooled slowly large crystals are
formed What is the difference between magma and lava?
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QUARTZ Quarts is one of the minerals that crystallize from
magma and lava.
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MINERALS FORMED FROM COOLING MAGMA OR LAVA Topaz: Magma that
cools forms Pegmatites. Crystals in Pegmatites are found in
Topaz.
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METAMORPHISM Temperature and pressure can cause atoms to break
bonds with other atoms creating new minerals.
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METAMORPHISM Graphite composed entirely of carbon atoms
transfers into a diamond under head and pressure.
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SOLUTIONS Minerals form from solutions by the water
evaporating. As water evaporates, the substances form into a solid.
Ex: gypsum forms as water evaporates: the mineral gypsum is left
after water evaporate hardens and gypsum is formed.
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HOW MINERALS ARE CLASSIFIED Based on chemical composition
Divided into two groups: Silicate minerals and nonsilicate
minerals
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SILICATE MINERALS Silicate minerals make up 90% of the Earths
crust. Minerals with silicon and oxygen are called silicate
minerals. Silicates are made up of repeating tetrahedron shaped
units. Feldspar Quartz
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SILICON TETRAHEDRONS One Silicate tetrahedrons are made of one
silicon atom bonded into four oxygen atoms Most silicate minerals
are composed of silicate tetrahedrons combined with other elements
like aluminum pg. 146
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NONSILICATE MINERALS Do not contain silicate tetrahedron
building block These minerals are made up of elements : carbon,
oxygen, fluorine, iron and sulfur.
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PROSPERITIES TO IDENTIFY MINERALS Color Color can be used to
identify a mineral. Streak the mark left by the mineral on a white
tile is the minerals streak. Streak is more reliable in detecting a
mineral than its color. Luster- When the mineral gives off a shine.
Two types of luster metallic and nonmetallic Cleavage: has a smooth
surface and parallel cracks running through the mineral. Book pg.
149 Fracture: uneven breaks throughout the mineral.
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PROPERTIES TO IDENTIFY MINERALS Density how much matter in the
substance. The density of the mineral pyrite can distinguish it
form gold. Hardness a minerals resistance to being scratched is its
harness. Scientists use Mohs scale to rate the minerals degree of
hardness. Pg. 150 If the reference mineral scratches your mineral,
the reference mineral is as hard or harder than your mineral. What
is the hardest known mineral and only the same mineral can scratch
it?