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Abalone
A mollusk whose shell is
iridescent on the inside. It is a source of mother of pearl,
extensively used in jewelry making.
Acroite
It is a type of tourmaline that is
rare and colorless.
Adamantine
A diamond like luster or glow.
Adularia
A common type of moonstone. This
whitish-bluish semi-translucent stone has a hardness of 6 and a specific gravity of 2.57.
Agate
A variety of chalcedony commonly found and
used in jewelry. It comes in a wide range of colors, like black, gray, brown, red,
green, pink. It can also be dyed to enhance the
coloration and the banding. Agate has a hardness of 6.5 to 7 and a specific gravity of 2.6.
The agate pin above is from Mirada.
Alexandrite
It is a mineral, a type of chrysoberyl that
change appears to colors in natural or artificial light.
Alexandrite appears to be red when seen in candle light and blue
to green when seen in fluorescent light.
Alexandrite Effect
It is a phenomenon in
which a stone appears to change colors when viewed in different
type of light, for example, the stone alexandrite
appears to be red when seen in candle light and blue to green
when seen in fluorescent light. Many other stones exhibit the
“Alexandrite Effect,” including garnet and sapphire.
Alloy
An alloy is a combination of two or more
metals. Common alloys used in jewelry are: gold under 24 Kt., sterling
silver, brass, bronze, and pewter.
Almandine
A kind of violet-tinged variety
of garnet that comes in range of colors from deep red to reddish-brown.
It is the most common kind of garnet. Almandine has a hardness of
7.5 and a specific gravity of 3.85-4.20.
Alpaca
It is an alloy
formed by mixing mostly copper, nickel and tin. It is used as a silver substitute.
Amber
A natural hydrocarbon,
Amber is translucent fossilized tree resin that comes in many colors,
like yellow, reddish, whitish, black, and blue. Amber is
flammable, Rubbing amber produces static electricity.
Amethyst
Amethyst is a form
of the mineral quartz. It is usually purple, varies in shades
from pale lavender to a very deep, reddish purple to a milky
color to green. Deeper colored amethysts are more highly valued.
Ametrine
It is a type of quartz, and mixture
of amethyst and citrine, thus it is partially purple and
partially orange-yellow in color.
Amorphous
The term Amorphous means without form.
It is used for the stones that do not have a regular internal
structure, like jet, amber, or ivory.
Amulet
It is worn for its protective charm as It is
said that it proptects the wearer from evil
or illness or bring good luck.
Angelskin Coral
A pale coral that comes from deep
sea coral. It is one of the most valued colors of
coral. Coral ranges in color from pale pink to orange to red to
white. In jewelry making, coral is either carved into beads, cameos,
or other forms, or is left in its natural branch-like form and
just polished. It used to be thought coral protected the wearer,
so it was traditional gift to children.
Annealing
Annealing is the process of heating a metal
and then cooling it to make it more workable. This process makes the metal
re-crystallize, putting the molecules in an orderly structure.
The temperature (and amount of time it takes) for annealing a
metal depends on what metal or alloy it is.
Anodized
Anodized metal it a form of metal that has been through an
electrochemical process known as anodization. It changes
the molecular structure of the surface layer, giving it a thin,
protective film. This process
causes a controlled oxidation of the metal’s surface to occur. Aluminum is
often anodized, as is magnesium, titanium, and tantalum, Anodized
metal has a lustrous sheen; the anodizing process can produce
colorful surfaces.
Aquamarine
A transparent, light blue or
sea-green stone belongs to the beryl family of stones. Today, blue aquamarines are more
highly valued. The best aquamarine are usually faceted but when
they are cabochon cut, a cat’s eye effect or asterism may appear.
It has
a hardness of 7.5-8 and a specific gravity of 2.65-2.85.
Aqua regia
Aqua regia is used to test gold and
platinum, it is a 3:1 mixture of hydrochloric acid and nitric
acid.
Arcade setting
An arcade setting is also known as coronet
setting. In this type of setting the stone is held in by many
metal claws around a metal ring.
Art and crafts
Arts and crafts was an artistic movement
that produced handcrafted pieces toward the end of the 1800’s.
The arts and crafts movement also
revived the art of enamel.
Assay
It is a test used to check the purity of an
alloy. A tiny piece of metal is scraped from the piece and the
percentage of gold or silver is determined. Official assay
offices determine whether a piece qualifies for an appropriate
hallmark.
Asscher cut
An Asscher cut, is a squarish step cut with
an almost octagonal outline. This style was developed by
Joseph Asscher who was an eminent diamond cutter, cut the 3,106 carat Cullinan diamond. This cut became very
popular in art deco jewelry and was a forerunner of the emerald
cut. Recently, the Royal Asscher Diamond Co. resumed production
of the original Asscher cut diamonds.
Asterism
An asterism is a star-like luminous effect
that reflects light in some gemstones.
Aventurine quartz
Aventurine quartz is a type of quartz that
has sparking flecks of mica or iron. The colors of
the stone include red-brown, yellow, gray, and green. This stone is usually cut with a flat or rounded surface to
maximize its sparkle. Aventurine quartz is found in India,
Russia, and Tenzania.
Awabi pearl
The Japanese name used for abalone pearls.
Axis of symmetry
An axis of symmetry or a
rotational axis is an imaginary line around which an object can
be rotated a certain number of degrees and look like the original
shape.
Azurite
It is a beautiful copper-based blue
mineral that is often used in jewelry. The color ranges from very
deep blue to pale blue. Azurite has also been used as a dye for
paints and luxury fabrics. Azurite has a hardness of 3.5 to 4
(relatively soft) and a specific gravity of 3.7 to 3.9. Azurite
is found in massive monoclinic crystals in Australia the
southwestern USA, France, Mexico, Morocco, Namibia, Zaire, and
Europe.
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