http://www.odditycentral.com/pics/the-crystal-cave-of-giants.html#more-1251
This is where you have to go if you want to see the biggest crystals on the planet.
Found in Naica mine of Chihuahua, Mexico, the Crystal
Cave of Giants is a chamber hosting some of the most
amazing crystals you’ve ever seen. They look like silver
or golden giants, and reach 11 meters in length, 1.5-2
meters in diameter and 55 tons in weight. Until 2007,
the reason for their abnormal size was unknown, but now
it’s clear it has something to do with mineral rich
water the crystals bathed in for millions of years
and the constant temperature that never drops bellow
150 degrees Fahrenheit.
Ever since it was uncovered, The Crystal Cave of Giants
has sustained considerable giant from the outside world,
so the mining company operating in the mine has installed
iron doors to seal off access.
http://news.nationalgeographic.com/news/2007/04/photogalleries/giant-crystals-cave/
April 9, 2007—Geologist Juan Manuel García-Ruiz
calls it "the Sistine Chapel of crystals," but Superman
could call it home.
A sort of south-of-the-border Fortress of Solitude,
Mexico's Cueva de los Cristales (Cave of Crystals)
contains some of the world's largest known natural
crystals—translucent beams of gypsum as long as 36
feet (11 meters).
How did the crystals reach such superheroic proportions?
In the new issue of the journal Geology, García-Ruiz
reports that for millennia the crystals thrived in
the cave's extremely rare and stable natural environment.
Temperatures hovered consistently around a steamy 136
degrees Fahrenheit (58 degrees Celsius), and the cave
was filled with mineral-rich water that drove the crystals'
growth.
Modern-day mining operations exposed the natural wonder
by pumping water out of the 30-by-90-foot (10-by-30-meter)
cave, which was found in 2000 near the town of Delicias
(Chihuahua state map). Now García-Ruiz is advising the
mining company to preserve the caves.
"There is no other place on the planet," García-Ruiz
said, "where the mineral world reveals itself in such
beauty."
http://news.bbc.co.uk/2/hi/science/nature/6518161.stm
Giant crystals enjoyed perfection
The cave was discovered in 2000
Enlarge Image
With lengths over 11 meters (36 feet), the giant gypsum
crystals found in
Mexico's Cueva de los Cristales are a great natural wonder.
Now, a Spanish-Mexican team thinks it can explain how these
marvels acquired their immense size.
The scientists studied tiny pockets of fluid trapped in
the crystals and conducted back-up lab experiments. They
report in the journal Geology that the solution from which
the crystals grew must have been kept in a very narrow,
stable temperature range.
The researchers' analysis leads them to believe there are
other dramatic caves waiting to be discovered in the
Naica mine complex south-east of Chihuahua city.
"If the theory we propose for the 'genetic' mechanisms of
the crystals is right, then I would not be surprised if
miners find more of these caves in the next few years,"
Juan Manuel Garcia-Ruiz, from the University of Granada,
Spain, told BBC News. And, in fact, one other has already
been found.
Already two remarkable caves are known at Naica, which
has yielded some of the world's most significant deposits
of silver and lead.
The 120 meter (394 feet) deep Cueva de las Espadas
(Cave of Swords), discovered in 1912, is named for its
metre-long shafts of gypsum (a calcium sulphate mineral
that incorporates water molecules into its chemical formula).
And although individually there are fewer crystals in the
290 meter (951 feet) deep Cueva de los Cristales, its
beams are considerably bigger.
Professor Garcia-Ruiz and colleagues believe they can now
show how these differences emerged.
The team studied tiny fluid samples embedded inside the
crystals themselves. These watery inclusions record
tell-tale chemical details of the saline and temperature
conditions of the saturated solution from which the
mammoth structures developed.
Both caves owe their origin to the volcanism which
laid down the metal sulphides - the ores - that have
proved so valuable.
Copious amounts of calcium sulphate would also have been
created towards the end of this mineralisation process
more than 20 million years ago - but in the hot fluids
that infused the cracks and cavities in the rock, this
calcium sulphate would have taken the form of anhydrite.
Anhydrite has the same chemical formula as gypsum, except
that it excludes water. Only as the magma chamber deep under
the Naica mountain cooled did the hot fluids above start to
fall to a temperature at which anhydrite could switch to gypsum.
Professor Garcia-Ruiz and colleagues say their studies
indicate that the deeper of the two caves - Cueva de los
Cristales - must have been kept just below the transition
temperature for many hundreds of thousands of years.
"The conditions were perfect. By maintaining the
temperature just below 58 degrees for a very long
time you get a few, very big crystals," said
Professor Garcia-Ruiz.
"You can see that many areas on the cave's walls are
empty; they have no crystals. The walls are red because
of the iron oxide. The reason we know this happened for
many years is because we studied the fluid inclusions
inside the crystals."
It is likely the upper cave - Cueva de las Espadas -
fell below the transition temperature much more
rapidly and consequently grew many, smaller crystals.
Heritage future?
The particular crystalline form taken by the gypsum
is selenite which is known for its translucency.
Their future will be dependent on the fate of the mine.
At the moment, access is restricted to prevent
damage to the soft crystals.
And humans can only get in the caves at all because
of the continuous pumping operations that keep them
clear of water.
If, when Naica's ores are no longer viable, the mine
is closed and the pumping is stopped, then the caves
will be submerged - and the crystals will start growing again.
"I've recommended to the mining company that they try
to preserve them and I would like to see Unesco get
involved," explained Professor Garcia-Ruiz.
"Later on we should decide whether to keep them
available for people to visit and enjoy, or let
the natural scenario return."
http://en.wikipedia.org/wiki/Selenite
Wikipedia
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http://www.crystalinks.com/mexicocrystals.html
The Naica Mine of Chihuahua, Mexico, is a working mine
that is known for its extraordinary crystals. Naica is
a lead, zinc and silver mine in which large voids have
been found, containing crystals of selenite (gypsum) as
large as 4 feet in diameter and 50 feet long. The
chamber holding these crystals is known as the
Crystal Cave of Giants, and is approximately 1000
feet down in the limestone host rock of the mine.
The crystals were formed by hydrothermal fluids
emanating from the magma chambers below. The
cavern was discovered while the miners were drilling
through the Naica fault, which they were worried
would flood the mine. The Cave of Swords is
another chamber in the Naica Mine, containing
similar large crystals.
The Naica mine was first discovered by early
prospectors in 1794 south of Chihuahua City.
They struck a vein of silver at the base of a
range of hills called Naica by the Tarahumara
Indians. The origin in the Tarahumara language
seems to mean "a shady place". Perhaps here in
the small canyon there was a grove of trees
tucked away by a small canyon spring.
From that discovery, until around 1900, the
primary interest was silver and gold. Around
1900 large-scale mining began as zinc and
lead became more valuable.
During the Mexican Revolution the mine was
producing a great deal of wealth. Revolutionary
troops entered the town and demanded money
from the owners. One of them was assassinated
when he refused to pay, causing the mine to
shut down from 1911 to 1922.
Just before the mine was closed, the famous
Cave of Swords was discovered at a depth of
400 feet. Due to the incredible crystals, it
was decided to try to preserve this cave.
While many of the crystals have been collected,
this is still a fascinating cave to visit.
In one part there are so many crystals on one
of the walls, they appear to be like an
underwater reef moving in a gentle undulating
motion in an ocean current.
In April 2000, brothers Juan and Pedro
Sanchez were drilling a new tunnel when
they made a truly spectacular discovery.
While Naica miners are accustomed to
finding crystals, Juan and Pedro were
absolutely amazed by the cavern that they
found. The brothers immediately informed
the engineer in charge, Roberto Gonzalez.
Ing. Gonzalez realized that they had
discovered a natural treasure and quickly
rerouted the tunnel. During this phase some
damage was done as several miners tried to
remove pieces of the mega-crystals, so the
mining company soon installed an iron door
to protect the find. Later, one of the
workers, with the intention of stealing
crystals, managed to get in through a narrow
hole. He tried to take some plastic bags
filled with fresh air inside, but the
strategy didn't work. He lost consciousness
and later was found thoroughly baked.
When entering the cave our group is issued
helmets, lanterns, rubber boots, and gloves.
One must then be driven by truck into the
main mining tunnel called Rampa Sn. Francisco.
While the vertical drop is approximately 1000
feet, the drive is almost a half mile long.
The heat steadily increases and women have been
observed to begin "glowing". The truck stops in
front of a concrete wall with a steel door. The
intense heat can prevent brain functioning.
At the end of the tunnel there are three or four
steps into the aperture of the cavern itself. It
is in this short tunnel. In this short distance
the temperature and humidity goes from being
uncomfortably warm to literally a blast furnace.
Momentarily, the penetrating heat is forgotten as
the crystals pop into view on the other side of the
"Eye of the Queen". The entire panorama is now
lighted and the cavern has a depth and impressive
cathedral-like appearance that was not visible on
earlier trips with just our headlamps.
When inside the great cathedral of crystals,
the pressure of intense heat create a gamut of
emotions and perhaps hallucinations. One can
only remain for a short period of time.
Geologists report that these natural crystal
formations are incredibly complex, yet so simple.
They have a magical or metaphysical personality
independent of their chemical structures. There
is a magma chamber two to three miles below the
mountain and that heat from this compressed lava
travels through the faults up into the area of the
mine. Super heated fluids carry the minerals the
miners are seeking as well as form the crystals.
The mine is ventilated; otherwise, it could not
be worked. Some parts, however, are not air-conditioned,
such as the Cave of the Crystals, and there you feel
the heat from the magma deep below. The fluids travel
along the Naica fault, enter voids in the bedrock,
and then form entirely natural structures that are
not easily explained scientifically.
In April 2000, the mining company became confident
that the water table on the other side of the fault
had been lowered sufficiently to drill.
When they did this, it is almost as if a magical
veil of reality was breached and an entirely new
world was discovered. Two caverns filled with the
Earth's largest crystals were immediately revealed.
More discoveries are expected to be made in this
magical kingdom of intense natural beauty.
Selenite, the gypsum crystal, named after the
Greek goddess of the moon, Selene, due to its soft
white light, is said to have many metaphysical and
healing benefits. Selenite powder has been used
cosmetically for thousands of years to enhance
one's natural beauty. It is believed that this
crystal assists with mental focus, growth, luck,
immunity, and soothes the emotions.