Gem
World Jewellers
Gemstone & Jewellery Glossary.
This handy glossary gives you the
meanings behind everyday gem and jewellery terminology, as
well as detailing the meanings of those more obscure and
rarely used words.
Alloy:
A mixture of two or more metals
frequently used in jewellery (e.g. 9 Karat Gold).
Asterism:
Asterism or the Star Effect is a
reflection effect 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 colourful play of glittering reflections from small
metallic inclusions. This phenomenon is commonly found in
Sunstone, Aventurine Quartz and Gold Stone.
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.
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.
Baroque:
This term was originally used to
describe a style of 17th Century European music, art and
architecture that emphasize the extravagant. In gemmology, it
is aptly used to beautifully describe irregularly shaped
Pearls.
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.
Bolt Ring:
A circular catch used for the
fastening of necklaces or bracelet chains.
Box Clasp:
A box like hollow housing with a
groove into which a tongue clicks into place to securely shut
the clasp.
British Hallmarking:
This protects the public against
fraud and traders against unfair competition. It let's you
know who made the jewellery, what is its guaranteed standard
of purity and what Assay Office tested and marked the
jewellery? (More About
Hallmarking...)
Brush Finish:
Also known as "Satin" or "Matte"
finish. This is a texturing technique used on jewellery metals
where a series of tiny parallel lines are scratched on the
surface with a wire brush.
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.
Cameos:
A gem carved in relief.
Carat:
A unit of weight measurement for
precious stones (not to be confused with "Karat", a term used
to denote gold purity).
Channel Setting:
A setting technique whereby
gemstones are held side-by-side by their girdles between two
long tracks of precious metal.
Chatoyancy:
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.
Clarity:
A gem's clarity is determined by
judging the amount and location of inclusions seen. Basically,
the higher the clarity grade, the higher the value of the gem.
Clasp:
Any type of attachment that joins
two ends of a piece of jewellery.
Claw:
A setting used to hold gemstones
in place also known as a "Collet".
Claw Setting:
This is the most frequently used
method of setting gems into jewellery. Small metal claws with
a vice-like grip are bent over the girdle of the gem to ensure
its secure and enduring position in the ring.
Cocktail Ring:
A large, slightly oversized ring
set with precious and/or semiprecious gems.
Collet:
A setting used to hold a gemstone
in place on a ring, also known as a "Claw".
Colour Change:
Colour change gems are those that
distinctly change their colour when viewed under two different
light sources. This phenomenon is commonly found in
Alexandrite,
Sapphire and Colour Change
Garnet.
Commesso:
Developed in Florence in the late
16th Century, Commesso is a technique of fashioning pictures
with thin, cut-to-shape pieces of brightly coloured,
semiprecious gems. Also called Florentine Mosaic, Chalcedony
is one of gem types typically used.
Created Gemstones:
These possess identical properties
to their natural counterparts (i.e.
optical, physical, and
chemical etc.) but are created in a laboratory not in nature.
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, so called because of its shape which is square with
rounded corners.
Double:
Similar to rolled gold but instead
of base metal the surface precious metal "Veneer" is bonded to
another precious metal, usually Silver or another Carat gold
of a different colour. Also known as "Onlay".
Drop Earring:
An earring that hangs below the
earlobe. Also known as a "Dangle" earring.
Faceted Gems:
Gems with geometrically shaped
flat polished faces.
Figaro:
Similar to the "Curb" chain, but
possessing alternately sized links.
Filigree:
A lace-like ornamental work
created from intricately arranged and intertwined wires.
Findings:
A general term used to cover a
variety of semi-finished components used in jewellery
manufacturing such as settings, joints and catches.
Fine Gold & Fine Silver:
The term used to describe precious
metals in their purest forms (i.e. unalloyed with no
additions).
Florentine Finish:
A cross-hatched decorative
technique engraved into the surface of a precious metal. The
lines are coarser and more deeply incised than the "Brushed",
"Matte" or "Finish" methods.
Foldover Clasp:
A clasp where the hinged part
opens, passes through a ring and snaps shut holding the ring
securely in place.
French Back:
An earring system for non-pierced
ears whereby the earring is attached to the earlobe by means
of tightening a screw.
Gallery Strip:
A length of precious metal which
has been pierced to produce a continuous series of claws. Used
for setting large semi-precious stones.
Gemstones:
Gems are specimens of minerals or
organic materials used for personal adornment that possess the
attributes of beauty, rarity, and durability.
Half Hoop:
An earring that is not fully
circular.
Hoop Earring:
A circular-shaped earring made
from precious metal wire or tubing.
Hallmark:
A stamped mark which is applied to
items of jewellery and silverware as a guarantee of
authenticity and acts as a safeguard to purchasers. (More
About Hallmarks...)
High Polish:
High polish refers to the
mirror-like surface of jewellery metal.
Illusions/Illusion Discs:
A disc of patterned metal which is
inserted into the top of a setting. The gem is then set into
and surrounded by the disc in order to give the illusion of a
larger gem.
Inclusions:
Most gems contain tiny natural
features called inclusions. Mostly microscopic in nature, they
are most easily glimpsed under magnification. Inclusions that
don't interfere with the brilliance, sparkle and fire of a gem
don't affect the value.
Inlay:
A decorative feature of an item of
jewellery, such as a gemstone.
Intaglios:
A gem carved in negative relief.
Iridescence:
Iridescence is the rainbow like
colour effects seen in some gems. This phenomenon is commonly
found in Opal, Ammonite and
Moonstone.
J Hoop:
A hooped earring design where the
shape is not circular, but elongated similar to the letter
"j".
Jump Rings:
A jump ring is an oval or round
ring of metal wire used at the end of a chain to which a clasp
or securing system is attached.
Karabiner:
A clasping system similar to the
bolt ring used for fastening chains.
Karat:
A term used to denote gold purity.
The designation for fine gold is 24K therefore 9K is 375 or
37.5% pure.
Ligne:
A unit of measurement generally
used to determine bangle widths. There are forty lignes to the
inch.
Lobster Claw Clasp:
A jewellery fastening or clasp
shaped like a lobster claw. It possesses a spring-loaded arm
to keep the clasp securely closed.
Matte:
A frosted, non-shiny surface
effect commonly used in precious metal jewellery.
Millgrain Edge:
An edge that has small beads or
ridges, giving the effect seen on the edge of a coin.
Multistripe:
A Karat gold product made up of a
combination of three different coloured alloys (red, yellow
and white) which are bonded together and when rolled gives a
stripy coloured effect.
Non-Faceted Gems:
Those Gems that do not have
geometrically shaped flat polished faces such as cabochons.
Omega Back:
A hinged fastening clasp that
closely resembles the Greek letter, Omega. Used to secure
earring posts to the ear.
Onlay:
A decorative feature of an item of
jewellery, such as a gemstone.
Pave Setting:
Pave settings produce a carpet of
brilliance across the entire surface of a piece of jewellery.
The surface is encrusted, or quite literally "paved" in
diamonds and gems, and the body of the jewellery is brought
vibrantly to life.
Pinwire:
A round wire used for the
manufacturing of brooch pins and earwires. The wire is
supplied hard so that it maintains its shape and rigidity
during use.
Pleochroic:
Different colours are displayed
when the gemstone is viewed from different angles. When
cutting most pleochroic gemstones, such as Iolite and
Tanzanite, cutters typically try to minimize the pleochroism
and maximize the single most prominent colour.
Post:
The pin-like component of an
earring that passes through the pierced earlobe. Usually held
in place by a fastening system behind the lobe, such as the
"Butterfly" clasp.
Post & Omega:
A hinged fastening clasp that
closely resembles the Greek letter, Omega. Used to secure
earring posts to the ear.
Rolled Gold:
A base metal alloy bonded to a
"Veneer" of precious metal.
Rope:
A style of chain in which the
links are intertwined to resemble a length of rope.
Safety Catch:
A secondary fastening used for
securing jewellery that guarantees the safety of the jewellery
should the main fastening break. Usually seen as a hinged loop
that snap closes one side of a clasp to the other.
Satin Finish:
Also known as "Brushed" or "Matte"
finish, this is a precious metal texturing technique used on
jewellery where a series of very fine parallel lines are
scratched on the surface to create a "Matte" texture.
Screw Back:
A highly secure earring fastening
system whereby a nut screws onto a threaded earring post.
Scrolls:
Also known as "Butterfly" clasps,
they are a component used in earrings. They attach the earring
to the ear by being slid down the post that pierces the ear.
Seal Set:
A "Signet" ring, which is set with
a semi-precious gem. A seal set ring differs from a gem set
ring in that the stone protrudes out of the ring surface and
is surrounded by an open rim rather than solid metal.
Setting:
This refers to the style in which
a gemstone is held in place in the jewellery. Commonly seen
settings include; bezel, pave, channel and claw.
Shank:
The round encircling body of the
ring.
Shoulders:
The upper part of the ring
positioned between the upper shank and the setting.
Simulated Gemstones:
These don't have the same
properties (i.e. optical, physical, and chemical etc.) as
natural gemstones but resemble the natural gemstone they
imitate.
Snap Bar Closure:
A hinged, straight bar that lifts
up and down to secure or release earrings.
Solitaire:
A single gem or diamond featured
in a simple setting style.
Split Shoulders:
A V-like split in the ring's
shoulders that joins the setting.
Spring Ring Clasp:
A rounded fastening consisting of
a circular wire inside a hollow, circular tube. Usually kept
shut by a coiled spring and frequently used in necklaces.
Sterling Silver:
A high quality silver alloy with a
minimum quality of 92.5% pure silver.
Tennis Bracelet:
A flexible, chain-like bracelet
made up of evenly matched gems or diamonds. There are many
variations of this popular bracelet style.
Tiffany Setting:
A round, six-pronged setting.
Popularized by Tiffany & Co., New York, the "Tiffany" setting
has long, slender claws flaring out from the base.
Toggle Clasp:
A fastening consisting of a ring
at one end of a bracelet or necklace and a short bar on the
other. The bar passes through the ring to sit across it,
securely fastening the two ends together.
Trapichism:
These are star-shaped rays that
emanate from the centre of gem in a hexagonal pattern. These
rays appear much like Asterism, but unlike Asterism, they are
not caused by light reflection from tiny parallel inclusions,
but by black carbon impurities that happen to form in the same
pattern.
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Tel: 01202 761764 Fax: 01202 751481