Quartz is the most abundant single mineral on
earth. It makes up about 12% of the earth's crust. It's no wonder that
Quartz has gained the reputation of being the "chameleon" of gemstones.
Pure Quartz often called "rock crystal" was used in ancient times to
make crystal balls and bowls.
In today's market we also see many
of the quartz varieties set in gold jewelry. Varieties such as amethyst,
citrine, rose quartz, onyx, agates, chrysoprase and numerous
others.
Quartz varieties are commonly separated into two
groups based on the size of the individual grains or crystals.
Macrocrystalline quartz has individual crystals that are distinguishable
with the naked eye. Cryptocrystalline quartz consists of individual
crystals too small to be easily distinguishable under the
microscope.
Some of the Macrocrystalline quartz varieties are:
Amethyst, Ametrine, Cat's-eye Quartz, Citrine, Rock Crystal, Rose
Quartz, Rutilated Quartz and Smoky Quartz.
The Cryptocrystalline
varieties of quartz may be separated into two types. fibrous and
microgranular. Chalcedony is the general term applied to the fibrous
Cryptocrystalline varieties. Agate is an example of a fibrous
cryptocystalline quartz. Carnelian, Chrysoprase
and bloodstone are
other chalcedony varieties.
Chert is the general term applied to
the granular Cryptocrystalline varieties of Quartz. Flint and Jasper are
examples. There are also Quartzites like Aventurine, that are rock not
mineral. Quartzites are basically interlocking macrocrystalline
quartz grains combine with other color giving minerals.
The
varieties of chalcedony are divided more by character than by color.
Chalcedonies are gemstones such as agate, jasper, common opal, onyx,
Chert and etc.
Many chalcedonies have grown in popularity
with the growing appreciation for carved gemstone. spheres, eggs and
ect. Unusual quartz types like drusy quartz, with it's tiny sparking
crystals and rutilated quartz, which has shining gold needles inside.
Are adding variety to one-of-a-kind jewelry projects.
Some of the more common of
these types are Chrysoprase (a pure green agate), Sard (a yellow to
brown agate), Sardonyx (banded sard), Onyx (black and white agate),
Carnelian (a yellow to orange agate), Flint (a colorful and
microscopically fibrous jasper), Jasper (a colorful opaque agate) and
bloodstone (a green with red speckled jasper) just to mention a
few.
Quartz Uses - Quartz is found in many
everyday items, including sandpaper and other abrasives, soap and
ceramics. It is also in high-tech items such as radios, TVs, Clocks,
watches and computers. It was found to be highly useful in modern
technology, because in electric tests, it was shown to produce regular
electric pulses and field changes that inventors could
predict.
Places Crystal Quartz is Found in Tanzania -
It is found in
Morogoro region, Tanga Region,Kilimanjaro Region, Iringa,Singida Region,
Mererani etc. All this areas the only Quartz found in abundance is milky
quartz. Its very very rare to get huge volumes of complete clean cyrstal
clear. Since at the beginning of the ground you will first find
milky Quartz as the Miner you will have to mine deeper to get rid
of Milky Quartz before you can reach the Clean Crystal Clear Quartz its
a highly costly laborous work. But it does also depend with the vein
Belt,if the vein belt from beginning of the ground it shows the clarity
within few metres of digging with mining tools you will reach high grade
quality Crystal quartz. Mostly is covered with kind of mud type sand. If
you happen to get a good vein, one vain can reach up to 300 kilometres
underneath the earth. The good part of it the vein never goes so much
deeper on earth. The costs involved in Mining Quartz they are not that
higher compare to costs of Mining gemstones such as Tanzanites
etc. Quartz like the ones shown on this page. We do get clear crystal
quartz but limited volumes. Milky Quartz availability can range from
1000 tons monthly while Crystal Clear Quartz wont reach more than 10
tons monthly. Also Crystal Quartz when left too long in a sunlight it
tenders to weaken up its transparency.
Quartz is also found
lining Geodes, in meteorites and in moon rocks. It is present in nearly
every other rock type. Sedimentary, igneous and metamorphic rock
contains quartz in one form or another and in varying concentrations. It
is essential in the formation of most igneous rocks, including Granites,
Granodiorites and Rhyolites.
The weathering of igneous rocks
removes most other minerals. But Quartz grains resist the erosion
process. They collect together and when compressed make Sedimentary
formations. When Sedimentary rocks containing Quartz enter a Metamorphic
process, the size of the Quartz grains change greatly.
Quartz has
a Trigonal crystal structure, containing four axes, three of which
intersect to form a plane, intersected by the fourth. Impurities
or disruptions during the formation process can form crystals that
contain encrustation's and or phantom crystals. Crystals can also form
hexagonal prisms, twinning, or double termination's. They can show up in
Geodes in any or
all of the Quartz forms.
Phantom quartz
shapes are sometimes present in the interior of quartz crystals,
outlining an earlier stage of the crystal's formation. These phantoms
are usually composed of other minerals such as chlorite or other
varieties of quartz . This leaves a coating on most or all of the
surfaces of the crystal during its growth. The crystal then resumes its
crystallization creating a phantom crystal outline within
itself.
One other mineral shares isostructural crystal formation
with Quartz. It is a very rare Phosphate called Berlinite (A1PO4).
Herkimer Diamonds are Quartz crystals with double termination's and
Tourmalinated Quartz contains hairs of Tourmaline
crystals.
Rutilations in Rose Quartz can create a star effect.
Rutilated Quartz is a variety of Quartz Crystal containing impurities of
Titanium Dioxide, that form needles within the Quartz. Some have called
it Venus? Hair Stone.
Smoky Quartz has colors that range from tan
to light gray which makes it rare in the mineral world .There are only a
few others, that display brown or black coloring. It is sometimes
misleadingly sold as Smoky Topaz.
