Rock Crystallization
Development
Ryan Weber & Shamim
Formoso
Santa Rosa Junior College
Engineering 45
Younes Ataiiyan
Semester Project
The Anatomy of a Crystal
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A crystal is a solid in which the constituent
atoms, molecules, or ions are packed in a
regularly ordered, repeating pattern extending in
all three spatial dimensions.
Many rocks and minerals contain crystals within
their structure. Crystals usually form when rocks
are heated then cool slowly. Crystals have a
regular internal structure and grow into a
distinct geometric pattern. Crystals can also be
grown from other crystals. No two crystals ever
grow the same way.
Types of Crystals
Different Molecular Patterns
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A single material can crystallize into different
molecular patterns under different conditions.
when carbon crystals form under great
temperature and pressure, they can become the
hardest of all known materials: the diamond.
If the crystals form under other conditions, the
carbon can take the form of graphite, commonly
referred to as "pencil lead," which is very soft,
opaque and black.
How to grow crystals
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Get saturated
solution in a hollow
bowl until ‘seed’ is
formed
Let ‘seed’ hang,
undisturbed, in
saturated solution in a
jar
Rock Salt
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This is the common
name for the mineral
"halite". Its chemical
formula is NaCl.
It is typically formed
by the evaporation of
salty water (such as
sea water) which
contains dissolved
Na+ and Cl- ions
Alum Contaminated
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This is what happens
when you add chromium
salts to the alum solution
before it crystallizes.
Chromium is included in
the resulting crystal
structure and imparts a
purple color. The intensity
of the color will depend
upon the amount of
chromium included.
Crystals come in all sizes
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The largest natural
crystals on Earth have
been discovered in two
caves within a silver and
zinc mine near Naica, in
Chihuahua, Mexico,
according to mine
officials. Reaching lengths
of over 20 feet, the clear,
faceted crystals are
composed of selenite, a
crystalline form of the
mineral gypsum.
The Eerie Crystal Skull
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Some people with a
mystical bend credit them
with strange,
supernatural powers.
Geologists marvel at their
size. Archaeologists
wonder who made them.
And nobody denies that
they possess an eerie,
horrible beauty
unmatched by almost any
other objects. They are
the crystal skulls.
Works Cited
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http://www.crystalinks.com/mexicocrystals.html
http://cst-www.nrl.navy.mil/lattice/struk.picts/b1.s.png
http://cst-www.nrl.navy.mil/lattice/struk.picts/f5_6.s.png
http://www.unmuseum.org/cryskull.htm
http://www.soest.hawaii.edu/GG/ASK/rock
salt.html
http://www.seawhy.com/xlalumcr.html