Arizona
State Rock and Mineral
Arizona is an
awesome state when it comes to Rocks and minerals. Arizona is the rockhounding
Mecca for all the rockhounds I know, largely due to the rock, gem and mineral
shows and events that draw collectors, sellers and miners from all around the
word, but also due to the variety of rocks and mineral that can be collected.
This guide will look at the most well-known rocks and minerals and provide some
locations and information. (please see our affiliate links to some great guidebooks
for rockhounding in Arizona, it cost you nothing extra and helps us to keep
rockhounding alive)
History
Arizona
Gemstones rocks and minerals have been collected for over 1000 years, Turquoise
was mined and used for jewelry and beads. Arizona has long been the major
producer of turquoise and a top producer of peridot and other gemstones. We
will look at the gemstones that Arizona is most famous for and a few other that
are notable.
Geology
Igneous and
metamorphic crystalline basement rock makes up much of Arizona, to the east at
one time water and shallow sea contributed sediments, thus area was limestone
formed. Pangaea was caused with the subduction (the sideways and downward
movement of the edge of a plate of the earth's crust into the mantle beneath
another plate) of the Farallon Plate this caused the volcanism the occurred
over most of this area into Nevada, and covered Arizona in volcanic debris and
sediments. These massive amounts of volcanic materials and sediments, along
with the hydrothermal activity created Arizona’s extensive mineralization, in
veins rich in copper, gold, silver, lead, zinc, and rare earth, weathering over
the years also created secondary minerals and deposits. (For a nice geological
map click the link here.)
http://data.azgs.az.gov/geologic-map-of-arizona/
Turquoise
Arizona remains the largest producer in the US of Turquoise and was
rightly designated as the official state gemstone in 1974. An in-depth
discussion of Arizona turquoise would rightly be a large book, we will look at
the basics here. Chemically, turquoise is of hydrous phosphate of copper and
aluminum, and often found in areas of large copper deposits and mines. In early
days much turquoise was taken and crushed with the ore, some miners would pick
out what they could. As turquoise became more and more valuable pockets of fine
turquoise would be hand mined, sometimes these finds are called “hat” mined
maybe due to the miners sneaking it out or due to the small pockets that would
be found. Several mines are notable and of the top 10 most desired turquoise,
and the most valuable.
Some Arizona turquoise localities are world-famous and produce turquoise with a
characteristic color and appearance. These mines include: Kingman (famous for
its "high blue" color and black matrix), Sleeping Beauty (known for
its soft blue color and lack
of matrix), Morenci (known for its dark blue color and pyrite-studded matrix),
and Bisbee (known for its high blue color and chocolate-color matrix). (see
links for turquoise at the bottom of the page)
Petrified Wood
Arizona is the source of world-famous
petrified wood, located close to Holbrook. Geologist state that millions of
years ago mass amounts of forest trees were buried in water sediments and then volcanic
ash, and then silica rich soil with a variety of minerals the slowly replaced
the wood cells with silica, and became chalcedony, and in some cases opal. The
minerals settle out with in the silicas and created many color variations. In
time these buried trees were uncovered by erosion to be found and enjoyed today.
Part of this area is set aside as the Petrified Forest National Park where you
may view but don’t touch or remove anything, so that generations to come may
enjoy this treasure. There are areas outside the park where we can collect.
(See guidebook links below)
Petrified wood can be beautiful in
its rough natural state or be cut and polished for lapidary arts including
jewelry. The beautiful colors include the following shades of brown, black,
red, orange, yellow, white, purple, gray, green.
Peridot
Beautiful
Peridot of gem quality is found in the basalt flows on the San Carlos Reservation,
also most peridot is mined from the Peridot Mesa and Buell Park areas at the
reservation. Arizona is the worlds top producer of Olivine AKA Peridot. Most
stones are under 5 carats and come in shades of yellow green to dark green,
with the darker green stones of high quality fetching the highest values.
Amethyst
Arizona
amethyst is highly sought after and the most important sight for mining it is
the Four Peaks Mine, located in Maricopa County, at about 6,500 feet elevation
here a beautiful reddish-purple amethyst is obtained. The
amethyst at Four Peaks is found as crystals in fractures and cavities in a
fault-brecciated quartzite of the Mazatzal Formation. Four Peaks amethyst
ranges in color from very pale purple to deep reddish purple, purple, and
purplish red.
Ant Hill Garnet is
a vived red and found in the Garnet Ridge area. They are rarely over 1 carat.
As you can gues by the name these garnets were first mined by ants that will mine
and deposit the small gems on their ant hill. Many of these gems are a red
chrome pyrope with a high color saturation, and can be faseted or made into
cachons for jewelery.
Gem Silica
Often
called Chrysocolla Chalcedony, due to the rich blues to greens, I have also
seen it so dark blue like lapis. These colors come from copper minerals with in the silica.
Supper nice spesimins and cabichons can sell by the gram. Gem silica is a rare material that
has only been produced at a few locations worldwide. The Miami-Inspiration Mine
in Gila County, Arizona is one of the most recent sources of gem silica. In the
early 1900s the Keystone Copper Mine, also in Gila County, has been a source of
gem silica.
Fire
Agate
Arizona fire
agate is one of the best. Few places in the world can brag to be the source of
the rare fire agate. Looking much like a fire opal it flashes iridescent colors
of brown, red, orange, green, and yellow. The curved botryoidal agate produced
light refractions due to the thin coatings of iron oxide, or iron hydroxide
within the stone, the colors change as the gem is turned, the curved surface is
causing the change in the colors of refraction. Cutting and polishing the fire
agate is tricky requiring following the curve of the botryoidal formations to
bring out the brightest colors. Relatively few people know of the gem outside
of us rockhounds and hard-core gem collectors yet is remains affordable in
comparison to its rarity.
Apache Tears deserve a notable
mention due in fact to the abundance of these novel collectables. I recall my Grandfather
telling me the story of how to hunt for these, he said go out when the sun is
low or after a rain sprinkle and the sun lights them up on the desert floor. These
are bits of volcanic glass obsidian usually black and translucent. They make a
great addition to every rockhounds collection and a great conversation piece.
Other Arizona Gems
To list all the great Arizona gems
would take a book, we have added a few others to put on your list when you go
to rockhound Arizona, these include, copper, and several copper minerals that
include azurite, malachite. Others include gold, agate, jade, jasper, onyx, opal.
Rockhounding Arizona: A Guide To 75 Of The State's Best Rockhounding Sites (Rockhounding Series) https://amzn.to/2TEJIi1
Turquoise (Updated): The World Story of a Fascinating Gemstone
Join me on the
Radical Rocks Podcast, our Blog or social media below, also
see our affiliate links below that help support our mission to keep Rockhounding
and lapidary arts alive and thriving. Feel free to contact me with any
suggestions on this blog or any other ideas you may have. If you would like to
sponsor in some way, or have your club, book, or mine, spotlighted in Radical
Rocks, Blog, Podcast or Video’s feel free to contact Shane with Radical Rocks
Affiliate/referral
links
Fundrise,
become a real estate investor for only $500 I have for months now and it’s been
earning an average of 10% dividends. https://fundrise.com/i/33o5g
Arizona Rock and Mineral collection rules file:///C:/Users/T979528/Downloads/2014%20Rockhounding_14_web.pdf
Arizona state information https://www.netstate.com/states/symb/az_symb.htm
Comments
Post a Comment
Thank you for your comment. I will review content for spam and such.