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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.



A mixture of two or more metals frequently used in jewellery (e.g. 9 Karat Gold).


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.


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.


The attachment at the top of a pendant that enables it to hang from the chain.


A ring which possesses the same width all the way round. Traditionally used for wedding rings.


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.


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.


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.


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.


A gem carved in relief.


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 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.


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.


Any type of attachment that joins two ends of a piece of jewellery.


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.


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.


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.


A style of chain in which the uniformly sized links are twisted to create a flat chain.


This refers to a style of "Signet" ring, so called because of its shape which is square with rounded corners.


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.


Similar to the "Curb" chain, but possessing alternately sized links.


A lace-like ornamental work created from intricately arranged and intertwined wires.


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.


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.


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.


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.


A decorative feature of an item of jewellery, such as a gemstone.


A gem carved in negative relief.


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.


A clasping system similar to the bolt ring used for fastening chains.


A term used to denote gold purity. The designation for fine gold is 24K therefore 9K is 375 or 37.5% pure.


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.


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.


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.


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.


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.


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.


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.


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.


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.


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.


The round encircling body of the ring.


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.


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.


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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