Following information is provided for you below - 24k gold, 18k gold,
14k gold - yellow, green and pink.
Precious stones and semi-precious stones from around the world.
Today's 24K Gold Market Price
(2) 22k Gold
(3) 18k gold
(4) 14K gold
(5) 14K green gold
(6) 14K pink gold
Four "C''s are:
(20) GIA* Color Grading
(21) Semi-Precious Stones:
(22) Semi-Precious Stones:
Swiss Blue Topaz
(23) Semi-Precious Stones:
(24) Semi-Precious Stones:
(25) Semi-Precious Stones:
(26) Synthetic Stones:
Faux Diamonds - Cubic Zirconia
(27) Freshwater Pearls
Gold is a very soft and malleable metal in its pure
form. It can be made slightly harder by drawing the metal
through a jewelers draw plate. 24k gold can also be rolled
through a rolling mill. 24k gold is extremely soft when annealed
for inlay jewelry work. To join pieces of 24k gold, they
should be fused. We use 24k gold in Mark Ehrmann Jewelry Designs
Keum-bu line of jewelry. 24k Gold is available in casting
grain, sheet, round wire, coins-Ancient
Byzantine gold coins and gold
bullion coins, 1 oz disc, and bullion
from 5-100 ozs. The beauty of 24k gold is that one may
also invest in
gold bullion. 24K pure gold has a chemical symbol of Au, it melts
at 1945 degrees Fahrenheit its specific gravity is 19.32 and its
weight is 10.180 in Troy ounces.
Gold has the 24k gold look but is made harder for
jewelry and dental use by adding 8.3% alloy. 22k gold can
easily be textured
and formed into beautiful jewelry. 22k gold can be easily
fused or soldered with 21k gold solder. American
Eagle gold coins are stamped by the United States Mint and are
made with 22k gold. (1.000 oz gold, 0.091 oz alloy). 22K gold is
also available in casting grain, sheet, round wire, sizing wire
and bezel wire. 22k gold is also used in the process of granulation.
gold is .752 fine, which is the European
standard of 18/24k gold and 6/24 alloy.
18K gold products are shanks for
rings, stone settings, sheet, wires, bezels, grain, and tubing.
There is also an 18k royal yellow gold that has more of an Italian gold
color which looks a little more green.
gold is .585 fine and is the
most used gold alloy in the United States. Rings, necklaces, pendants,earrings,
bracelets primarily made from 14k gold. 14k gold has less than
4% zinc which makes it suitable for enameling jewelry.
green gold contains gold, silver,
copper and zinc. Copper is the main hardening agent in karat
gold's (nickel in white gold's) but since it is used in such a small
percentage in green gold, these alloys are softer than karat gold's
in other colors. The greenest metal is obtained by alloying
to 18 karat. This also produces the softest green gold so there
usually is no need to anneal 18K green. 14k green is popular
because it provides a nice contrast when grouped with pink and white
pink gold contain the same metals
as yellow gold, which are gold, silver, copper, and zinc.
The pink color comes from a higher percentage of copper in the alloy.
Pink gold's anneal the same way as yellow gold's. To anneal 14k gold,
heat metal to cheery red color (1400 degrees F) and then quench or let
metal air cool. The hardness in the different karats of pink gold
also resemble yellow gold. Pink gold produces are becoming fashionable.
Pink gold is available in casting
grain, sheet, bezel strip, round wire, and sizing wires.
gold's contribution to the history of Mankind
recognizable by its yellowish cast, is one of the oldest metals used by
humans. As far back as the Neolithic period, humans have collected gold
from stream beds, and the actual mining of gold can be traced as far back
as 3500 B.C., when early Egyptians (the Sumerian culture of Mesopotamia)
used mined gold to craft elaborate jewelry, religious artifacts, and utensils
such as goblets.
Gold's aesthetic properties combined with its physical properties
have long made it a valuable metal. Throughout history, gold has
often been the cause of both conflict and adventure: the destruction
of both the Aztec and Inca civilizations, for instance, and the early
American gold rushes to Georgia, California, and Alaska.
The largest deposit of gold can be found in South Africa in the Precambrian
Witwatersrand Conglomerate. This deposit of gold ore is hundreds of miles
across and more than two miles deep. It is estimated that two-thirds of
the gold mined comes from South Africa. Other major producers of gold include
Australia, the former Soviet Union, and the United States (Arizona, Colorado,
California, Montana, Nevada, South Dakota, and Washington).
Without the discovery of gold in Nevada, it has been stated that the Union
would not have been able to fund the army and all the military campaigns
that would eventually win the Civil War.
About 65 percent of processed gold is used in the arts
industry, mainly to make jewelry. Besides jewelry, gold is also used in
the electrical, electronic, and ceramics industries. These industrial applications
have grown in recent years and now occupy an estimated 25 percent of the
gold market. The remaining percentage of mined gold is used to make a type
of ruby colored glass called purple of Cassius, which is applied to office
building windows to reduce the heat in the summer, and to mirrors used in
space and in electroscopes so that they reflect the infrared spectrum.
(8) Physical Characteristics
Gold, whose chemical symbol is Au, is malleable, ductile,
and sectile, and its high thermal and electrical conductivity as well as
its resistance to oxidation make its uses innumerable. Malleability is the
ability of gold and other metals to be pressed or hammered into thin sheets,
10 times as thin as a sheet of paper. These sheets are sometimes evaporated
onto glass for infrared reflectivity, molded as fillings for teeth, or used
as a coating or plating for parts. Gold's ability to be drawn into thin
wire (ductility) enables it to be deposited onto circuits such as transistors
and to be used as an industrial solder and brazing alloy. For example, gold
wire is often used for integrated circuit electrical connections, for orthodontic
and prosthetic appliances, and in jet engine fabrication.
Gold's one drawback for use in industry is that it is a
relatively soft metal (sectile). To combat this weakness, gold is usually
alloyed with another member of the metal family such as silver, copper,
platinum, or nickel. Gold alloys are measured by karats (carats). A karat
is a unit equal to 1/24 part of pure gold in an alloy. Thus, 24 karat (24K)
gold is pure gold, while 18 karat gold is 18 parts pure gold to 6 parts
is usually found in a pure state; however, it can also be extracted from
silver, copper, lead and zinc. Seawater can also contain gold, but in
insufficient quantities to be profitably extracted—up
to one-fortieth (1/40) of a grain of gold per ton of water. Gold is generally
found in two types of deposits: lode (vein) or placer deposits; the mining
technique used to extract the gold depends upon the type of deposit. Once
extracted, the gold is refined with one of four main processes: floatation,
amalgamation, cyanidation, or carbon-in-pulp. Each process relies on the
initial grinding of the gold ore, and more than one process may be used
on the same batch of gold ore.
In lode or vein deposits, the gold is mixed with another
mineral, often quartz, in a vein that has filled a split in the surrounding
rocks. Gold is obtained from lode deposits by drilling, blasting, or shoveling
the surrounding rock.
Lode deposits often run deep underground. To mine underground, miners dig
shafts into the ground along the vein. Using picks and small explosives,
they then remove the gold ore from the surrounding rock. The gold ore is
then gathered up and taken to a mill for refinement.
Placer deposits contain large pieces of gold ore (nuggets)
and grains of gold that have been washed downstream from a lode deposit
and that are usually mixed with sand or gravel. The three main methods used
to mine placer deposits are hydraulic mining, dredging, and power shoveling.
All methods of placer deposit mining use gravity as the basic sorting force.
In the first method, a machine called a "hydraulic giant" uses
a high pressure stream of water to knock the gold ore off of banks containing
the ore. The gold ore is then washed down into sluices or troughs that have
grooves to catch the gold.
Dredging and power shoveling involve the same techniques
but work with different size buckets or shovels. In dredging, buckets on
a conveyor line scoop sand, gravel, and gold ore from the bottom of streams.
In power shoveling, huge machines act like shovels and scoop up large quantities
of gold-bearing sand and gravel from stream beds.
Hydraulic mining and dredging are outlawed in many countries
because they are environmentally destructive to both land and streams.
the gold ore has been mined, it usually is washed and filtered at the
mine as a preliminary refinement technique. It is then shipped to mills,
where it is first combined with water and ground into smaller chunks.
The resulting mixture is then further ground in a ball mill—a
rotating cylindrical vessel that uses steel balls to pulverize the ore.
Separating the gold from the ore.
gold is then separated from the ore using one of several methods. Floatation
involves the separation of gold from its ore by using certain chemicals
and air. The finely ground ore is dumped into a solution that contains
a frothing agent (which causes the water to foam), a collecting agent
(which bonds onto the gold, forming an oily film that sticks to air bubbles),
and a mixture of organic chemicals (which keep the other contaminants
from also bonding to the air bubbles). The solution is then aerated—air
bubbles are blown in—and the gold attaches to the air bubbles. The
bubbles float to the top, and the gold is skimmed off.
Cyanidation also involves using chemicals to separate the gold from its
contaminants. In this process, the ground ore is placed in a tank containing
a weak solution of cyanide. Next, zinc is added to the tank, causing a chemical
reaction in which the end result is the precipitation (separation) of the
gold from its ore. The gold precipitate is then separated from the cyanide
solution in a filter press. A similar method is amalgamation, which uses
the same process with different chemicals. First, a solution carries the
ground ore over plates covered with mercury. The mercury attracts the gold,
forming an alloy called an amalgam. The amalgam is then heated, causing
the mercury to boil off as a gas and leaving behind the gold. The mercury
is collected, recycled and used again in the same process.
The carbon-in-pulp method also uses cyanide, but utilizes
carbon instead of zinc to precipitate the gold. The first step is to mix
the ground ore with water to form a pulp. Next, cyanide is added to dissolve
the gold, and then carbon is added to bond with the gold. After the carbon
particles are removed from the pulp, they are placed in a hot caustic (corrosive)
carbon solution, which separates the gold from the carbon.
If the gold is still not pure enough, it can be smelted.
Smelting involves heating the gold with a chemical substance called flux.
The flux bonds with the contaminants and floats on top of the melted gold.
The gold is then cooled and allowed to harden in molds, and the flux-contaminant
mixture (slag) is hauled away as a solid waste.
Because gold is a finite resource, its long-term future
is limited. In the short term, however, it will continue to find widespread
use in jewelry and in industrial applications, especially in the electronics
the last few years, several companies have focused on extracting gold
from sulphide ore rather than oxide ore. Previous techniques made such
extraction difficult and expensive, but a newer technique called bio leaching
has made extraction more feasible. The process involves combining the
sulphide ore with special bacteria that "eat" the ore or break
it down into a more manageable form.
Diamonds are mined in many parts of the world,
but 80% of the stones on the market today come from Angola, Australia,
Botswana, Namibia, South Africa, Russia and Zaire. All of these sources
might appear to indicate great availability, but this is not the case. More
than 250 tons of ore need to be blasted, crushed and processed to yield
just one carat of rough diamond. Most of the rough extracted from the ground
is not suitable for gems; only about 20% of all rough diamonds are suitable
for gem cutting.
Mohs Hardness: 10 /Refractive index:2.417
/Specific Gravity: 3.515 /Treatment: none
Four "C''s are:
Color-Diamonds can cover the entire spectrum of colors. They
range from having a perceptible yellow or brownish tint up to those rare diamonds
described as colorless. Colorless diamonds allow the most reflection of
light and are therefore the most desirable. Off-white diamonds absorb light,
inhibiting brilliance. You can best observe diamond color by placing the
stone table-side-up on a flat white surface or grading trough, and examining
it from different angles. Next, place it table-side-down with the
culet facing you, and examine it through the pavilion facets.
The cut of the stone
the greatest influence on a diamond's fire and brilliance, A
round, brilliant-cut diamond has 58 facets. When well-proportioned,
this shape best shows the stones's brilliance because it allows the
most light to be reflected back to the eye of the observer. Stones
that appear lifeless or seem dark in the center are probably poorly
cut. When the angle relationship between the crown and pavilion
facets is correct, rays of light entering the diamond strike the rear
facets at an angle greater than the critical angle (24.5 degrees for
a diamond) and reflect back to the eye of the observer. If the
stone is cut too deeply, the light strikes the rear facets at an angle
less than the critical angle and the light is lost through the sides
of the diamond. If the stone cut is too shallow, the light passes
through the diamond without being reflected back.
diamonds contain internal stress fractures and minute traces of non-crystallized
carbon. These inclusions are usually not apparent to the naked
eye but can be seen in loose stones under magnification. "Perfect
means that no inclusions are detected when the stone is examined
under a 10X lens. Inclusions absorb light, preventing
it from being reflected back through the front of the stone. Their
effect on the diamond's value varies with the size, number
and location. An inclusion in the center, beneath the
table, is more visible than one near the edge and may be mirrored
by the facets, magnifying the dulling effect.
term "carat" originates from the ancient practice of weighing
diamonds against the seeds of the carob tree. the system was
eventually standardized with one carat fixed at 0,2 grams. Each
carat is sub -divided into 100 points, so a quarter-carat is 25 points
of 0.25 carat. Although the carat is a unit of weight, not size,
the carat weight of a diamond has come to refer to particular sizes. If
properly cut, diamonds of the same weight should be about the same
size. These sizes don't apply to other gems, however, because
their specific gravities are different from diamonds and from each
come from the South American
country, Columbia. Emeralds differs from others gems, as Type III
gems, because they are the only major gemstone expected to have visible
inclusions; in fact, any specimen without them is immediately suspect as
a synthetic or an imitation.
The Emerald belongs to the beryl family and gets its green
color from traces of chromium and vanadium. Many emeralds
are treated with an oil to enhance their color. Clarity
is measured using a jeweler’s loupe (a small magnifying
glass used to view gemstones) under 10-power magnification. Because
each emerald forms under its own, unique circumstances, each
individual gemstone is comprised of a combination of trace minerals,
which lend a precise color as well as unique identifying marks
or inclusions. “Jardin” or “gardens” are
natural inclusions you see in all the Emeralds, at naked eye
or with magnification, this allow emeralds show the mystery and
beauty of the most desire gemstone in the history. The wonderful
gardens are the birthmark of emeralds that make differ of Natural
Emeralds to synthetic emeralds. There is not two Emerald internal
gardens that match. The best clarity for emeralds
is VVS or i1, minute inclusions to 10x and fine emeralds can
start with SI1or i4 clarity scale.
Mohs Hardness: 7.5-8 /Refractive
index:1.560-1602 /Specific Gravity: 2.68-2.78 /Treatment: Oiled
Rubies are a variety
of corundum and is one of the worlds most valuable gemstones. The ruby's
color is due to a trace of chromic oxide: the amount of this substance determines
the depth of the ruby color. Because of the hardness and durability, rubies
are an excellent choice for all types of jewelry. r\Ruby is the birthstone
for the month of July. The earliest
record for the mining of rubies goes back to more than 2,500 years ago in Sri
Lanka. Historically, many believe that mystical powers lie within this intensely
colored red gemstone. When inserted beneath the skin, the ancient Burmese believe
that the stone generates a mystical force, which protects the wearer from accidents
and attack. In the ancient world, many believed rubies to contain prophetic powers,
enabling wearers to predict their future based on the color changes of their
gemstones. The ancient Hindus enchanted by the color of rubies considered them
to be "Ratnaraj" or the "King of Precious Stones". The
modern word ruby is derived from the ancient Latin term "Rubeus".Today,
Burma is the world's largest provider of high quality rubies. Many consider Burmese
rubies from the Mogok Valley to be the world's finest. Vietnam, Kenya, Tanzania
and Sri Lanka are some of the other providers of this truly enchanting gemstone.
Thailand, with large deposits near the Cambodian border, was previously the world's
largest provider of rubies, but due to environmental regulations, the mining
of gemstones has been greatly reduced. Rubies and sapphires are closely related,
having corundum as their base mineral. The difference in color occurs because
of the different trace minerals contained within each gemstone. Thai rubies tend
to have a darker color and less intensity than Burmese rubies, which are known
for their high quality and high price range; however, very fine rubies can be
found in Thailand at very affordable prices. African rubies tend to have heavy
inclusions, but beautiful stones with fine clarity can be found, usually in the
higher price range.
Mohs Hardness: 9 /Refractive index:1.760-1.770
/Specific Gravity: 4 /Treatment: Usually Heat treated
are a corundum, a crystallized
oxide of aluminum. They contain traces of titanium and iron, which are
what give sapphires their blue color. If other mineral traces are also
present, a sapphire may have a color other than blue, such as yellow, pink,,
orange, violet or green. A corundum gem that is not red or blue is known
as a "Fancy
Sapphire" Sapphires have strong refraction,
which favors the use of the same brilliant cut that is used on diamonds. Sapphires
have a moderate dispersion. They do not have as strong a dispersion as diamonds,
and thus they do not share the diamond’s “fire".
Rubies and Sapphires, both are corundum and are basically
the same gem, except that rubies are always red and sapphires
can be a variety of color. Sapphires are mined mainly
in Australia, Myanmar (Burma), Kashmir, Sri Lanka, Thailand,
Vietnam, Afghanistan, Pakistan, and Cambodia. Some of the best
sapphires come from Sri Lanka. Australian sapphires are deep
blue to nearly black. Montana, USA, has metallic blue sapphires. Many
of the best blue sapphires come from Kashmir, but production
has dropped off greatly due to political strife in that area.
Kashmir sapphires do not change color under electric lights,
while sapphires from other places take a navy blue tint under
electric lights. Small, needlelike inclusions called rutile
silk often deepen the blue and soften the Kashmir sapphires.
Rutile silk often increases the quality of a gem, although
it can sometimes cause the gem to lose brilliance, making them
of little value. Sapphires usually occur in crystals
of twelve-sided prisms. Most sapphires have faults, and some
have silky-looking internal patches.
It is believed that about ninety percent of sapphires and rubies
are heat-treated to increase the quality of their color. This
treatment is accepted as bona fide in the gem business, and
it is unlikely the trend will change. Slight flaws are also
sometimes burnt out of the gems. A sapphire, especially
a blue one, should first be worn only after trial. Even a perfect
sapphire is sometimes unlucky and will cause trouble to the
user. To test a blue sapphire one can wear the gem wrapped
in a blue cloth bound around one’s arm for a week. One
can also place it under his pillow for three nights. If there
is any bad effect, the sapphire should be rejected. Blue
Sapphire (Neelam) Cornflower-colored sapphires are considered
the most valuable. Blue sapphires without flaws, with evenly
distributed color, that are well-cut and brilliant, are the
Mohs Hardness: 9 /Refractive
index:1.760-1.770 /Specific Gravity: 4 /Treatment: Usually
Color Grading Scale
Color Grading Scale
Swiss Blue Topaz
Faux Diamonds - Cubic Zirconia
(27) Freshwater Pearls
Freshwater and salt water pearls may sometimes look quite similar, but they come from different sources. Freshwater pearls form in various species of freshwater mussels, family Unionidae, which live in lakes, rivers, ponds and other bodies of fresh water. These freshwater pearl mussels occur not only in hotter climates, but also in colder more temperature areas such as Scotland (where they are totally protected by the law). see freshwater pearl mussell. However, most freshwater cultured pearls sold today com from China.
Back to top
|Mark Ehrmann Jewelry Designs
© | Contact