COMPOSITION &
ENVIRONMENT:
Green Aventurine Quartz, is actually a quartzit, It is a rock,
not a mineral. It is composed essentially of interlocking
macrocrystalline quartz grains and other color imparting minerals.
Usually formed by metamorphism (metamorphism is the alteration of a rock
due to changes in heat, pressure or chemical environment.) When a quartz
rich sedimentary deposit or a sandstone undergoes metamorphism the
original material alters to a compact rock. Composed of interlocking
quartz grains known as quartzite. Most of the aventurine quartz is
filled with tiny platelets of a green chromium mica, called fuchsite.
Although some aventurines contain different varieties of mica, hematite
or other sparkly inclusions. These colorful specks add sparkle and also
create or help create the body color of the aventurine they
inhabit.
DISTINGUISHING CHARACTERISTICS
As you move a piece of aventurine. The
sparkling inclusions produce reflections causing a glittering effect. In
the gem trade this effect is known as aventurescence. Over the centuries other gems and even
types of man made glass have been called Aventurine. An explanation for
the name aventurine comes from the 1700's. A similar looking man made
glass called Goldstone, was reported to be discovered by chance. In
Italian, the words (a ventura) mean, by chance. Hence the term
aventurine. Two different feldspar gems, both typically a goldish
reddish color. Have also been associated with the term aventurine. All
of the materials called aventurine are filled with small lustrous specks
that reflect light. What those specks are, depends on which aventurine
you�re talking about. Goldstone is filled with tiny metallic copper
crystals. One of the sunstones, the labradorite feldspar, is filled with
tiny copper crystals that have exsolved (separated out of the crystal
lattice). The other sunstone, an oligoclase feldspar, is filled with
tiny crystals of exsolved hematite, which produce reddish
inclusions.
LOCALITIES:
Deposits are found in Brazil, India, Austria, Russia, and
Tanzania. India produces the majority of the world�s aventurine quartz.
Most of which is a greenish color. The best green aventurine comes from
the region of Bellary. A town in the state of Mysore in south central
India, 270 miles northwest of Madras. Besides the material from India.
Green Aventurine Quartz may also come from Brazil, Madagascar and
several other occurrences of good green material are found around the
world, including the United States. Some of the nicest sunstone verity
comes from the state of Oregon. In Czarist times, Siberia produced some
of the finest aventurine, found in the Korgon Mountains of Tomsk
Province. There is also some new Russian aventurine on the market since
the fall of the Soviet Union. Aventurine quartz of redish brown, or an
orange-yellow are also widespread. But these are seldom as striking as
the green. These other colors are generally due to the flakes of mica
being stained by iron oxides or hydroxides.Sometimes the flakes are
hematite rather than mica.
USES
All of the above aventurines are more
or less only used as lapidary materials. Whether it be the attractive
natural greens, blues or peach colors. Found in the more recognized
quartzite verities of aventurine. Or the shimmering copper colors found
in sunstone and goldstone. Very fine grades of Green aventurine that
show little, if any, of the sparkling impurities. Has been miscalled
Indian jade. It is usually pretty easy to tell the difference just look
into the stone with a 10 power hand lens and see if you can see the very
small mica flecks. Sometimes the flecks are so small that other
gemological instruments are needed. These grades are probably as rare if
not more rare than the jade they mimic. Probably not something to worry
about too much.
FACTS & HISTORY
The astrological sign of green
aventurine quartz is Aries. Green aventurine quartz can be an alternate
birthstone for the month of August.
Records from the late 1800's
show that aventurine was being imported to the German gemstone center of
Idar-Oberstein. After World War I, these lapidaries were importing the
material in quantity and are still doing so today. American dealers have
been importing it since World War II. Today a good deal of aventurine
quartz is sold as beads.
One of the most impressive examples of
cut aventurine is an obelisk carved by HelmutWolf. A famous carver from
the village of Kirschweiler near Idar-Oberstein. It stands 5-1/2 feet
high and weighs 2.5 tons. It was cut from fine green Indian
Aventurine.
It is suspected that
aventurine is the only gemstone in which the man made gem was know
before it's natural counterpart.
GREEN AVENTURINE IN
TANZANIA
Here in Tanzania Green
Aventurine is mostly found in Babati, a district within the Arusha
region plus other Regions in Tanzania. This are mainly coming out
larger pieces, one piece can weigh up to even 5 tons. But due to luck of
latest mining equipments for Mining such large pieces which they need an
open cast Mining. Most mined Green Aventurine here in Tanzania doesnt
weigh more than 1 Ton they use Dynamites to break it into smaller
pieces so that they can be transported easily.
The Green Aventurine found here in
Tanzania in huge volumes is mostly Greenish in Colours.
Green Aventurine
boulders stocks.
OUR STOCKS / ORDER
SPECIFICATIONS
Minumum
Order Supply - 2 kilograms
Maximum Order
Supply - 100 tonnes.
PRICE & SHIPPING COSTS (FOB/CIF). SEND US AN
EMAIL FOR THE QUOTATION.
sales@seabgems.com
