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AGATE:
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ALEXANDRITE: Click
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ALLOCHROMATIC GEMS: The colors in these "other-colored"
gemstones come
from trace elements or impurities that are not an essential part of their
chemical composition. A good example of an allochromatic gem type is corundum,
which when pure is colorless, but when impurities such as metal oxides
are present corundum can be transformed into the red
gemstones we
call rubies or the blue, green, yellow and padparadsha we call sapphires. Allochromatic
gems
are susceptible to color enhancement through different forms of
treatment. See
IDIOCHROMATIC GEMS.
ALLOY: A mixture of two or more metals frequently used in jewelry
i.e.18 Karat gold. Please refer to the
Precious Metals Buyer's
Guide for more information.
ALLUVIAL DEPOSITS: Amounts of material that have been separated
from the host rock by a process of weathering then deposited by streams
or rivers.
AMBER: The gemstone
Amber is the fossilized sap, resin, or gum from trees. This precious gem
ranges in color from shades of golden yellow to golden orange, but brown,
green, red and violet amber has been found. Transparent to translucent,
amber gemstones normally occur in small irregularly shaped masses. Amber
gems may contain insects, lichen, moss and sometimes animals such as lizards
and frogs that were trapped millions of years ago when the resin was sticky.
Amber is quite soft and is perfect for jewelry as it can be easily cut,
etched, faceted, or carved. Before amber gems were used for medicinal
purposes but today, this gem type is used almost exclusively in jewelry
such as necklaces, brooches, pendants and rings.
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catalogue of this gem type.
AMERICAN BRILLIANT CUT: The American brilliant cut is a method
of cutting diamonds to mathematical perfection for greatest brilliancy
and fire, today's most popular cut for fine stones. It is employed in
Europe as well as in the United States. Sometimes shortened to "American
Cut".
AMETHYST:
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AMETRINE:
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AMMONITE:
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AMORPHOUS: An irregular internal atomic structure or external shape.
ANDALUSITE:
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APATITE: Click
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APOPHYLITE:
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AQUAMARINE:
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ART DECO: An angular style of jewelry dating from the 1920s through
the mid to late 1930s, featuring jade, black onyx, and pave-set diamonds.
ART NOUVEAU: A free-flowing, curved, revolutionary style of jewelry
popular from the 1890s until about 1910, featuring delicate enamels with
precious and non-precious materials in the characteristic motifs of bats,
morning glories, dragonflies, and women with long, flowing hair.
ASTERISM: Asterism is the star effect that appears on some gemstones
when cut EN CABOCHON. The star effect is a reflection that appears as
two or more intersecting bands of light across the surface of a gem. This
phenomenon is commonly found in Ruby, Sapphire and Garnet.
AVENTURESCENCE: Aventurescent gems are those that have a colorful
play of glittering reflections from small metallic inclusions. This phenomenon
is commonly found in Sunstone, Aventurine Quartz and Gold Stone.
AXINITE: Click
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AZURITE: Click
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BAGUETTE: French for "rod". A step cut used
for rectangular stones, chiefly those of small size.
BAIL: The attachment at the top of a pendant that enables it to
hang from the chain.
BAND: A ring which possesses the same width all the way round.
Traditionally used for wedding rings. Please refer to the
Jewelry Setting Buyer's
Guide for more information.
BANGLE: A rigid bracelet that either slips over the hand or is
clasped on.
BAR SETTING: These are short bars that run
like a railway track across a ring. Gemstones are individually set between
these bars leaving the sides of the stones exposed to light. This technique
maximizes the amount of light entering the gemstones creating superior
brilliance and sparkle. Please refer to the
Jewelry Setting Buyer's
Guide for more information.
BASAL PINACOID: A feature that relates to crystal symmetry. A columnar
or prismatic crystal with flat ends can sometimes be referred to as having
a basal pinacoid.
BERYL: Click
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BEZEL: A component used to mount settings to ring shanks.
BEZEL SETTING: A "Bezel" setting is a crafted diskette of metal that
holds the gemstone by its girdle to the ring, securely encircling the
entire circumference of the gem. Variations of the "Bezel" setting are
the "Flush" and "Gypsy" settings. Please refer to the
Jewelry Setting Buyer's
Guide for more information.
BIREFRINGENCE: The difference between the highest and the lowest
refractive indices in doubly refractive gemstones.
BIRTHSTONES:
12 gemstone types corresponding to the 12 months of the year. Believed
to bring luck to those who wear them, birthstones originate from the breastplate
of Aaron (the brother of Moses) & the correlation of gems with astrological
signs in ancient India.
January -
Garnet,
February -
Amethyst,
March -
Aquamarine,
April -
Diamond,
May -
Emerald,
June -
Alexandrite,
Pearl &
Moonstone,
July -
Ruby,
August -
Peridot,
September -
Sapphire,
October -
Opal
&
Tourmaline,
November -
Topaz
&
Citrine,
December -
Tanzanite,
Turquoise
&
Zircon.
BOLT RING: A circular catch used for the fastening of necklaces
or bracelet chains.
BORACITE: Click
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BOTRYOIDAL: A form similar to a bunch of grapes.
BOX CLASP: A box like hollow housing with a groove into which a
tongue clicks into place to securely shut the clasp.
BRUSH FINISH: Also known as "Satin" or "Matte" finish. This is
a texturing technique used on jewelry metals where a series of tiny parallel
lines are scratched on the surface with a wire brush. Please refer to
the Precious Metals
Buyer's Guide for more information.
BUTTERFLIES: A component used in earrings.
The "Butterfly" attaches the earring to the ear by being slid down the
post of the earring that pierces the ear. Also known as "Scroll" pieces.
CABOCHON / EN CABOCHON: A simple style of cut - flat
bottomed and a highly polished domed top - used to display colors and
optical effects in opaque and translucent gemstones.
CAMEO: A stone or shell cut in relief, using the natural colors
of the stone or shell to produce the different shadings of the carving.
Opposite of intaglio. See INTAGLIO.
CANNETILLE: Metal jewelry made from fine wires, often in a pyramid
or rosette motif.
CARAT: A unit of weight denoting the size of both uncut and cut
gemstones. There should be 100 points to a carat (ct.). The newcomer to
diamond buying should be careful not to become so influenced by carat
size that he or she ignores or fails to recognize the importance of such
points as clarity, color, and cut. (Not to be confused with "Karat", a
term used to denote gold purity).
CARIBINER: A clasping system similar to the bolt ring used for
fastening chains.
CARLETONITE:
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CARVING: Refers
to the cutting of decorative objects from a larger mass. Popular gem types
used for carving are Azurite, Blue John, Malachite, Rhodochrosite, Rhodonite
and Serpentine.
CAT'S EYE:
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CERUSSITE:
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CHAMPLEVE ENAMEL: A process in which the sections containing various
colored enamels are carved out of the surface of the base, rather than
formed by soldering thin strips of metal to the base, as in cloisonné
enamel.
CHANNEL SETTING: A setting technique whereby gemstones are held
side-by-side by their girdles between two long tracks of precious metal.
Please refer to the
Jewelry Setting Buyer's Guide for more information.
CHAROITE:
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CHATELAINE: A decorative plaque with a hook attached at the rear,
to be worn from a belt or sash around the waist. A series of plaques or
chains suspended from it held purses, watches, keys, sewing utensils,
note pads, pencils, buttonhooks, and other functional implements.
CHATOYANCY: Or the Cat's Eye Effect is a reflection effect that
appears as a single bright band of light across the surface of a gemstone.
This phenomenon is commonly found in
Chrysoberyl,
Tourmaline and
Tigers Eye.
CHRYSOBERYL:
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CIRCA (c. or ca.): Represents the approximate period of time in
which an item was made.
CITRINE: Click
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CLASP: Any type of attachment that joins two ends of a piece of
jewelry.
CLAW: A setting used to hold gemstones in place. Also known as
a "Collet". A claw consists of a "Bezel" and "Prongs". Please refer to
the Jewelry Setting
Buyer's Guide for more information.
CLEAVAGE: Cleavage is when a gemstone breaks along lines of weakness
related to the internal atomic structure.
CLOISONNE ENAMEL: A type of enamel-work in which thin strips of metal
are soldered to the base of the piece to form the outlines of the design.
Colored enamel is then placed in each section.
COBALT: Click
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COCKTAIL RING: A large, slightly oversized ring set with precious
and/or semiprecious gems.
COLOR CHANGE: Color gems are those that distinctly change their
color when viewed under two different light sources. This phenomenon is
commonly found in Alexandrite,
Sapphire and
Color Change Garnet.
COLORED DIAMONDS:
Diamonds are found in a variety of colors, generally very pale, including
brown, green, pink, blue, red, and yellow. When these colors are intense
and well balanced throughout the stone, premium value is likely to be
attached. But a diamond of pastel color is not as desirable as a
colorless or "white" diamond.
COLLET: A setting used to hold a gemstone in place on a ring. Also
known as a "Claw". A "Collet" consists of a "Bezel" and "Prongs". Please
refer to the Jewelry
Setting Buyer's Guide for more information.
COLOR GRADE: The color quality of a diamond, expressed according
to a scale of letters representing different grades of color. Crystal
clear, or absolute lack of color, is the most desirable. These are often
referred to as "white"
diamonds.
COLORLESS: A diamond in which no trace of color can be detected.
The ideal state for stones intended for the round brilliant cut. Truly
colorless diamonds are worth a premium over others, assuming they
are not severely flawed.
COLUMNAR: A kind of habit in which crystals form in the shape of
columns.
COMPOSITE GEMSTONE: A gemstone assembled from several pieces, often
used to imitate a gem.
CONCHOIDAL FRACTURE: A shell like fracture.
CORNELIAN:
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CREEDITE:
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CROWN: The crown is the top part of a cut stone, situated above
the GIRDLE.
CRYPTOCRYSTALLINE: A mineral structure in which crystals are so
small they are not distinguishable with a microscope.
CRYSTAL:
A crystal is solid material that has a definite internal atomic structure;
this produces a characteristic external shape and physical and optical
properties.
CRYSTAL STRUCTURE: The internal atomic structure of a crystal.
All crystalline gems may be classified in one of seven groups, according
to the symmetry of their structure: cubic, tetragonal, hexagonal, trigonal,
orthorhombic, monoclinic and triclinic.
CURB: A style of chain in which the uniformly sized links are twisted
to create a flat chain.
CUSHION: This refers to a style of "Signet" ring stamping. So called
because of its shape, which is square with rounded corners.
CUT: The cut is a term used to refer to the way a gemstone is FACETED.
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