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AMBER – An organic material made of fossilized tree resin, Mohs hardness of 2.

AMETHYST – A purple variety of quartz with a hardness of 7. The Greek for amethyst was amethystos which means "not drunk". The stone was thought to protect against drunkenness. For this reason goblets were sometimes made of amethyst.

ANTIQUE – Any item judged to have been made at least 100 years ago.

AQUAMARINE – A bluey green transparent variety of beryl, the name is meant to suggest the colour of seawater. 7.5 - 8 on the Mohs scale. Aqua in ancient times was credited with aiding sleep, protecting sailors and counteracting the effects of poison.

ART DECO – Characteristic geometric design form begun in the late nineteenth century and specifically associated with the period from 1920-1935.

ART MODERN/ART RETRO – An extension and modification of ART DECO into the 1940's & 50's.

ART NOUVEAU – Characteristic flowing lines based on natural forms, 1890's-1910.

ARTS & CRAFTS MOVEMENT – Characterized by handmade silver and enamel pieces set with rough or flawed stones: movement strongest from 1900 to 1910.

BAGUETTE – Small gems cut in the form of narrow rectangles or tapered trapezoids.

BAILEY, BANKS AND BIDDLE – Founded in Philadelphia USA in 1878 -Sucessor to Bailey & Co. George W. Banks and Samuel Biddle joined forces with Joseph T. Bailey II in 1878 and formed Bailey, Banks and Biddle. The name was changed to Bailey, Banks and Biddle Co. when the company incorporated in 1894. It is currently thriving and is now owned by the Finlay corporation.

BANGLE – A bracelet which is not flexible.

BAROQUE PEARL – An irregular shape more common than spherical may be natural or cultured.

BASE METAL – Any non-precious metal.

BASKET MOUNT – Describes the area where the sides and part of the shank of the ring head are in an openwork basket shape.

BASSE-TAILLE – A method of enamelling in which the surface of the metal is hollowed out to receive the enamel. Similar to 'CHAMPLEVE'. The design in the base metal was first made by chasing, carving, engraving, stamping or engine-turning, and then the surface was covered with transparent or translucent coloured enamel that is then fused by firing in a kiln.

BEAD-SET – Beads of metal, which secure the stone flush with the mount as in pav

BERYL – Family of stones with a hexagonal crystal system including, Emerald, Aquamarine, Red Beryl, Morganite and green beryl.

BEZEL SET – A collar of metal burnished over the girdle of the stone.

BLUE-WHITE – A diamond term sometimes used to infer the finest colour.

BOHEMIAN GARNET – A loosely used term to indicate the small dark red rose-cut garnets used regularly in the late nineteenth century.

BOMBÉ – Convex shaped, often used in period jewellery, particularly in bracelets and brooches.

BOODLE AND DUNTHORNE – Founded in 1798 in Liverpool. Boodles remains steadfast to its original principles of designing and crafting jewellery themselves and has been owned by the Wainwright family since 1880.

BOUCHERON – The House of Boucheron is a French family dynasty founded by Frederic Boucheron in 1858. Moving to the current headquarters at 26 Place Vendome in Paris in 1893, Boucheron has been patronised by numerous Kings, Queens and stars of stage and screen. Including among others, The Queen, The Queen Mother, Tsar Nicholas II, Greta Garbo, Rita Hayworth, Nicole Kidman and Cameron Diaz.

BRIGHT CUT – A deep, sharply cut engraving in metal, associated with the Victorian Period.

BRIOLETTE – An oval or teardrop shaped stone covered with small triangular facets.

BUFF-TOP – A stone cut with cabochon crown (top) and faceted pavilion (bottom).

C-CLASP – A simple closure in the shape of a "C" found on antique brooches.

CABOCHON – A polished, not faceted, dome shaped stone - either round or oval with a flat polished base, primarily used as a cut for phenomenal stones such as cat's eyes and stars.

CALIBRÉ – Any stone specially cut to fit a particular mount.

CAMEO – The process of carving in order to leave a raised design (above the table of the stone) on a single piece of material. Opposite of Intaglio.

CANNETILLE – Open coiled wirework a technique popular during the first half of the nineteenth century.

CARAT – A unit weight of gemstones, 1ct is equal to 0.2 grams. Originally from the uniform weight of the carob seed.

CARAT GOLD – Any solid alloy of gold with other metals, below a fineness of 24ct but more than 10ct, may be stamped showing the actual fineness, for example "18ct Gold".

CARTIER – Maison Cartier was founded in Paris in 1847 by Louis-François Cartier when he took over the workshop of his master. In 1874 his son, Alfred Cartier took over the company, but it was Alfred's sons Louis, Pierre and Jacques, who were responsible for establishing the world-wide brand name of Cartier. Louis retained responsibility for the Paris branch, moving to the Rue de la Paix, in 1899. He was responsible for some of the company's most celebrated designs, like the mystery clocks, fashionable wristwatches and exotic orientalist Art Deco designs, including the colourful "Tutti Frutti" jewels. Cartier also created the famous Panthère brooch of the 1940's for Wallis Simpson. Jacques took charge of the London operation and eventually moved to the current address at New Bond Street. Pierre Cartier established the New York City branch in 1909, moving in 1917 to the current location of 653 Fifth Avenue, the Neo-Renaissance mansion of Morton Freeman Plant which Cartier bought in exchange for $100 in cash and a double-stranded natural pearl necklace valued at the time at $1 million. Cartier has since become synonymous with glamour and prestige.

CARTOUCHE – Shield or scroll (shape) usually has Hallmark or Punchmark with in.

CASTELLANI AND GIULIANO – Founded by Fortunato Pio Castellani in 1816 the house of Castellani has been solely credited with style of Italian Archaeological Jewellery. Influenced almost totally by the Duke of Sermoneta, Fortunato focused on reviving Etruscan methods of granulation in his jewellery. The Duke's friends included Stendhal, Chateaubriand, Liszt and Balzac which would have given the Castellani important connections throughout Europe. In 1851 Fortunato retired and left the business to his two sons, Alessandro and Augusto. Augusto was the driving force rather than Alessandro who had lost an arm in an accident and was imprisoned for his political views. Later he was temporarily declared insane. He was then exiled and became the company's foreign representative. They opened in London with Carlo Giuliano as the manager in 1861 in Frith Street. Specialising in Greek and Etruscan jewellery with all the technical expertise that entailed. They branched out to Christian symbolism and Byzantine-style micro mosaic and complex enamelling. By 1896 the business had moved to 115 Piccadilly and Carlo gave it to his sons Carlo and Arthur Giuliano. No one has been able to reproduce the extremely high quality of workmanship before or since. The jewellery bearing these hallmarks is some of the most collectable in the world. The business was closed in 1914.

CASTING – Formed by pouring molten metal into a mould.

CAT'S EYE – A well defined streak of light along a cabochon (chatoyancy).

CHALCEDONY – A semi-transparent to translucent form of quartz.

CHAMPLEV – An enamel technique, employing an etched design filled with enamel. See "Cloisonn

CHANNEL SET – Rows of gems secured by metal flanges, with no claws or beads used.

CHENIER – A tube of metal cut and set as a cross section, normally under the gallery or shoulders.

CHYRSOBERYL – Most common variety is "cat"s eye chrysoberyl" (see above) known for its honey and milk colouration of two separate colours divided by a clearly defined line. Alexandrite is a rare variety, this is a colour change stone and is green in daylight and purplish red at night.

CIRCA OR CA – Means "approximately", usually with regards to dates.

CLADDAGH RING – A Claddagh ring has a distinctive design, two hands clasping a heart, and typically surmounted by a crown. This is often said to correspond to the qualities of love (the heart), friendship (the hands), and loyalty (the crown). The expression which was associated with these symbols in the giving of the ring was: "With my hands I give you my heart, and crown it with my love."

CLAWED COLLET – A collet set with integral triangular shaped flat claws, typically early nineteenth century. See "BEZEL SET".

CLEAVAGE – A break parallel to a cleavage plane. Possible only in some stones i.e., Topaz, Diamond, Fluorite, Tanzanite and some others rarely used in jewellery.

CLOISONN – An enamel technique within cells created by soldering wire to a base. See "Champlev

CLOSED-BACK SETTING – A setting where the pavilion (bottom) of the stone is enclosed. The stone may be foil backed. Caution; do not immerse jewellery with closed back settings in any liquid.

COLLET-SET – See "BEZEL SET".

COMPOSITE – Early plastics - including celluloid, bakelite, gutta-percha, etc. earliest date to 1850's.

CORAL – Organic material, seen in the earliest examples of jewellery.

CROWN – Relating to a stone, the portion of the stone which is above the girdle (widest area).

CRUCIFORM – Items in the form of a cross.

CULET – A small facet polished across the pavilion (bottom) point of a faceted stone. Larger culets are popular on old cut diamonds.

CULTURED PEARL – Forced introduction of a bead nucleus into a mollusc, stimulating the animal to secrete layers of "Nacre" over it, which forms a cultured pearl. Note, the use of the word "pearl" alone means "natural". See "Natural Pearl". Mohs hardness of 2.5

CURB CHAIN – Flattened, ovoid oval chain links.

CUSHION CUT – A square or rectangular stone with rounded corners and deep crown facets, found mostly in antique jewellery.

DEMI-PARURE – A small suite of jewellery, usually a brooch and earrings or necklace and earrings.

DIAMOND – Diamond is the hardest of all gemstones (and the hardest naturally occuring mineral on earth)with a score of 10 on the Mohs scale. The word comes from the Greek word 'Adamas' meaning invincible. The diamond has been a highly prized gemstone for the last three thousand years.

DOUBLET – A two part assembled stone. Used to enhance colour or imitate a stone. Do not immerse in fluids. Most commonly used in for opals to protect the thin layer, see "triplet".

EDWARDIAN – Description used for the period during the rule of Edward VII 1903-1910.

EMAIL EN RONDE BOSSE – Enamel on an object in the round. Opaque enamel is applied thickly on a raised or metal surface to form a relief decoration.

EMERALD – Emeralds are a variety of the Beryl family coloured green by trace amounts of chromium and sometimes vanadium. Beryl scores 7.5 - 8 on the Mohs scale. Most emeralds are highly included, so more care is recommended when wearing. The word "emerald" comes from the Greek 'Smaragdos' meaning green.

EMERALD-CUT – A rectangular step-cut with 45-degree corner angles.

ENAMEL – A pigment of vitreous nature composed usually of powdered potash or silica bound with oil coloured with glass as a surface decoration by low-temperature firing.

ENCRUSTATION – An overlay of gemstones, gold, etc., on the surface of another substance.

ENGINE TURNED – Machine engraving to produce design and/or brilliance, often a base for enamel or on larger items to give a pattern.

ENGRAVING – Ornamentation using chisels or engravers to cut away design.

ESSEX CRYSTAL – An item made of Rock Crystal carved and engraved from behind and then hand painted, these pieces are highly collectable.

FACETING – Polishing a gemstone into a series of flat planes for maximum beauty and brilliance.

FILIGREE – A fine wire bent and soldered to create a usually very intricate design.

FILIGREE ENAMEL – Decorating in the manner of cloisonn

FLORENTINE FINISHES – Cross-hatched lines on modern or pseudo antique items.

FLORENTINE MOSAIC – A type of mosaic made in Florence, composed of tiny pieces of opaque varicoloured hard stones, selected and arranged so that the colours and gradations of tones create a pictorial effect, usually of flowers or scenes, that is cemented on a background of white or black marble. See Mosaic "Micro-Mosaic" & "Pieta Dura".

FLUORESCENCE – The varying colour effects produced when materials are subjected to ultra-violet light.

FOB – A seal or other decorative items suspended from a man's watch chain.

FOIL BACKED – A thin metal foil behind a stone in a closed-back setting which adds colour and/or brilliance.

FRACTURE – A break of any sort other than cleavage which may occur in any stone.

FRENCH JET – Black glass made to resemble jet.

GALLERY – On a ring, the area below the setting, usually described as pierced, carved, etc.

GEMMOLOGY – The study of gemstones.

GEORG JENSEN – In 1904 he risked everything and opened his own small silversmithy at 36 Bredgade in Copenhagen. Jensen's training in metalsmithing along with his education in the fine arts allowed him to combine the two disciplines and breathe new life into the tradition of the artist craftsman. Soon, the beauty and fine quality of his Art Nouveau creations caught the eye of the public and his success was assured. The Copenhagen quarters were greatly expanded and before the close of the 1920's, Jensen had opened retail outlets in New York, London, Paris, Stockholm, and Berlin. Georg Jensen died in 1935, but in the preceding years he imbued the firm with his strongly held ideals concerning both artistry in design and excellence in craftmanship, this tradition has been adhered to throughout the twentieth century. Although Jensen himself was a proponent of the Art Nouveau style, he had the wisdom and foresight to allow his designers their own freedom of expression which expanded the stylistic scope of what the firm produced and allowed it to keep step with time. It is because of this timelessness that Georg Jensen pieces are so highly prized by collectors the world over.

GILDED OR GILT – Dipped in gold.

GIRANDOLE – A pendant, brooch or earrings with swinging pear-shaped drops.

GIRDLE – The middle of a fashioned gemstone, it divides the crown and pavilion.

GOLD FILLED – Layer(s) of gold joined to base metal. Similar to rolled gold. Fraction may indicate ratio of gold content to total weight.

GRANULATION – Application of tiny gold beads to a plain surface by soldering. Employed extensively by the ancient Etruscans, the process was lost until the 19th century when it was rediscovered by experimentation's carried out largely by the celebrated Italian, Fortunato Castellani. Typical of the Etruscan style popular in the mid-nineteenth century

GRISAILLE – Layer(s) of white enamel over grey ground produces a monochromatic effect. A type of decoration in painted enamel in which the picture or design is monochrome - usually shades of grey on a white background.

GYPSY SETTING – A stone sunk into a mount with the table flush with the mount surface. Usually there are one to three stones in the ring.

HAIR COMPARTMENT – A glass compartment on the reverse side of a piece of jewellery which held hair of a friend, lover, or relative, but not necessarily a memorial piece of jewellery. Popular mid-nineteenth century.

HAIR JEWELLRY – Braided or designed human hair made into jewellery (i.e. lockets, brooches, etc.) for memento or memorial.

HALLMARK – System of marking precious metals, but not required on antique jewellery.

HANDKERCHIEF RINGS – Identified by a loop attached to the back of the ring through which a handkerchief was passed, popular with the Victorians.

HOLOLITH RING – A ring cut from one piece of gem material.

ILLUSION SETTING – Metal surrounding a stone making it appear larger than it is, by working the metal in such a way that it looks like an extension of the stone.

IMITATION – A substitute for an "authentic" thing.

INLAY – To set in a surface to form a decoration. The process of decorating by inserting shaped pieces of material (not enamel) into the surface or ground of an object so that the surfaces of both are level.

INTAGLIO – Material carved (worked) so that the design is cut into the surface of the material (incised). Opposite of cameo.

IRRADIATED DIAMONDS – Enhancement of colour in diamonds by radiation. Colour in diamonds may be enhanced by this treatment. The effect of radiation on diamonds was first discovered in 1904 by Sir William Crooks but did not become widely used by the jewellery trade until after 1960.

IRRIDIUM – Used as an alloy for platinum to create a hard metal. Platinum is generally alloyed with 3% copper; if a harder metal is wanted, the alloy is 10% iridium and for a medium hard alloy, 5% is used. The hardness of irridium also makes it serviceable for pen nibs.

JADE – The term covers two distinct types of stones: jadeite, the Chinese jade, and nephrite, the New Zealand greenstone (often confused for jade). Jadeite is rarer and more precious. Jade from Burma and southern China ranks as the finest in the world, along with jadeite from Siberia.

JASPER – An opaque, compact form of quartz which occurs in shades of dark red, brown, yellow, green and grey. Used especially for larger decorative pieces.

JET – A hard black variety of coal or lignite. Specimens are known from the Bronze Age. The main source since Roman times is the Yorkshire coast in England near Whitby. Whitby jet, particularly, was a favourite of Queen Victoria during her widowhood.

KARAT – Measurement of the fineness of gold. Pure gold is 24 Karat. Continental standards are marked as decimals, i.e., .750 for 18k, .375 for 9k, etc.

KEEPER RING – Wide band of bold deeply engraved and worn above the wedding ring to prevent its loss. Some were incised with the word "Mizpah" (The Lord be between me and thee when we are absent one from the other). Popular in the 18th and 19th centuries.

KHESHI – A by-product of the salt water culturing pearl process, produces small rice shaped pearls.

LACE RINGS – For holding the folds of a scarf or lace fichu - fashionable in the second half of the 18th century.

LAPIS LAZULI – Laps lazuli is an opaque stone with gold flecks (iron pyrites) and calcite. Ground lapis lazuli was used by artist's as a pigment until replaced by ultramarine.

LASER – (Light Amplification by Stimulated Emission of Radiation). The first practical development was by Dr. Theodore Maiman, then of Hughes Aircraft Corp. in 1962, who proved the 1959 theory of Dr... Charles H. Townes, of Massachusetts Institute of Technology. Pulses of co-ordinated light beams are set up within a rod or crystal - ruby or YAG or a tube of helium and neon gases. The waves bounce back and forth until tremendous energy is build up. They are then released in a straight beam and focused to a sharp point. Such beams have been used in eye surgery and to bounce light from a mirror on the moon. The concentrations of energy at the focal point produce intense heat which can burn out carbon or other inclusions in a diamond.

LATEN (LATTEN) – Brass, a mixture of copper and zinc. A common metal of the Middle Ages. It resembles gold in colour and is much softer than bronze.

LAVALIERE – A delicate pendant(s) worn on or attached to neck chains.

LIDDICOATITE – A new variety of tourmaline, named after Richard T. Liddicoat. It has a hardness of about 7.5 on the Mohs scale. It is similar in colour to the elbaite tourmaline with zones of red, pink, and blue in many specimens.

LIMOGES – A type of enamelwork on copper in the style of 'champlev

LOOP – The suspension loop on a pendant, locket, watch etc.

LORGNETTE – A pair of eye glasses mounted on a handle; opera glasses similarly mounted.

LUCKENBOOTH BROOCHES – Heart shaped brooches, the name presumably because they were sold in the Luckenbooths street stalls (locked booths) near St. Giles Church, Edinburgh. They were often pinned to the shawl worn by a child at its christening to ward off evil.

LUSTRE – Eight types of lustre are recognized by the gemmologist: (1) Adamantine - characteristic of diamonds only, (2) Vitreous, the appearance of broken glass (sapphire, ruby, emerald, topaz, tourmaline and rock crystal), (3) Metallic, opaque gemstones (Hematite and pyrite are examples), (4) Pearly (Moonstone and opal), (5) Waxy, Turquoise, (6) Resinous, having the appearance of resin (Amber), (7) Silky, fine green malachite, and (8) Oily like the sheen of oil (Chrysolite).

MABE PEARL – Mabes are assembled after culturing. There fore, all Mabe cultured pearls are assembled cultured pearls.

MAKER'S MARK – Initials or trademark stamped or engraved on a piece.

MALACHITE – From the Greek malache, from its green colour. A dark green stone with bands of various shades of green. It is hydrated copper carbonate. Found in the Ural Mountains, Tagilsk in Siberia, Zaire and Zimbabwe.

MARQUISE – Stone or item of jewellery that is essentially oval but has pointed ends.

MATRIX – Parent (or host) rock. Term usually associated with turquoise or opal. Also the base of a signet ring.

MAZARIN CUT – See "single cut".

MELE – Assortment of small diamonds of mixed sizes, normally under 0.20ct.

MICRO-MOSAIC – Small pieces of glass (tesserae) grouted to form a design so fine that the design may appear to be painted.

MILLEGRAIN – A type of setting for stones in which tiny beads of the metal are raised to grip the girdle and so enhance the sparkling effect.

MOCHE AGATE – Similar to moss agate. Inclusions are manganese oxide, which produce arborescent markings. It is found especially in Montana and Wyoming USA.

MOHS SCALE – A table of comparative hardness devised by the Austrian mineralogist, Friedrich Mohs. Based on the ten relatively common minerals which are ranked from 1 to 10 in order of increasing hardness: (1) talc (2) gypsum (3) calcite (4) fluorite (5) apatite (6) feldspar (7) quartz (8) topaz (9) corundum (10) diamond. A fingernail will scratch gypsum and softer substances. Ordinary window glass is slightly softer than feldspar. Almost all-important numbers in the scale indicate only the order of hardness and bear no relationship to quantitative hardness. That is, there is a greater difference between the hardness of corundum and diamond (9 and 10) than between 1 and 9.

MOSAIC – Pieces of glass or gems set in grout. See "Micro-Mosaic" & "Pietra Durra". An object decorated with many small adjacent pieces of inlaid varicoloured glass or stone arranged to form a picture of design. For articles of jewellery. The mosaic was usually made in the form of medallions set in brooches, pendants, and necklaces. Finger rings, earrings and parures.

MOSS AGATE – A type of chalcedony. Varying amounts of oxide of iron inclusions produce moss like effects.

MOUCHOIR BAGS – Handkerchief bags.

MOURNING OR MEMORIAL – Remembrances of dead friends, relatives, employers, etc. This type of jewellery may have hair compartments, engraved with details, and enamelled (usually black or blue). See "hair Jewellery". Introduced in the 17th century.

MOURNING RING – Rings made especially to mark the death of a loved one. Often called 'memento mori' rings. Rare examples survive intact and are highly collectable.

NACRE – Iridescent layers of six - sided crystals of aragonite (calcium carbonate) held in a web - like deposit of conchiolin to which pearls owe their luminous beauty.

NATIVE CUT – Term used to indicate irregularities of facts. Common in jewellery prior to the early twentieth century.

NATURAL PEARL – A pearl bearing mollusc that has not been tampered with in any way by man to produce a pearl. The use of "pearl" alone means natural. See "Cultured Pearl".

NAVETTE CUT – The marquise or pointed oval.

NICKEL SILVER – An alloy of 65% copper, 5 to 25% nickel, and 10 to 30% zinc.

NIELLO – A black material (sulphur, lead silver & copper mixed) used to fill engraved work on silver or gold.

OLD CUT – Refers to a diamond cut with a circular shape and large CULET with the table diameter usually 50% or less then that of the girdle and a high crown. These diamonds were cut to maximise light return in low light conditions. Also called an Old European Cut.

OLD MINE – Refers to a diamond cut with a cushion shape, large CULET. Developed in the late seventeenth century it was used up until the South African diamond mines opened around 1875

OLD MINE DIAMOND – Mined before the African mines either Brazil or India

OLIVINE – See Peridot.

ONYX – A form of chalcedony with black land white bands. Often carved into cameos, cups and vases and other decorative objects.

OPAL – The word "opal" is of doubtful origin but probably came from Sanskrit upala, meaning precious stone. This beautiful gemstone is a solidified jelly, not a crystal as are most of the other principal gemstones. Its exact nature is not completely understood. The varying refractive index of the thin layers of which precious opal is composed gives it its distinguishing characteristics. The principal fascination with precious opal comes from the infinite variety of colour display. The main constituent is silica (SiO2Hs0) with the water content varying from 3 to 10%. Opal has hardness of 5.5 to 6.5 on the Mohs scale. All types of opal will crack if treated harshly; some will crack even when given the best of care. Much precious opal occurs in thin layers. For use in jewellery, this opal is cemented to a backing material before being set in jewellery. The materials most often used as a backing are common opal (called potch), onyx and a ceramic mater. The result is called a doublet. The top layer, or opal, is still subject to exposure and wear and can suffer damage. This problem is solved through the creation of colourless quartz cemented to the top. This protective layer not only protects the opal layer; it also enhances the appearance of the opal itself.

OXIDIZED SILVER – Has a blackened finish from immersion in potassium sulphide, etc.

PALLADIUM – A silver white metallic element belonging to the platinum group. It has good working properties and weighs half as much as platinum making it a favoured for use in large earrings.

PARURE – A matching set (suite) of antique jewellery consisting of a necklace, earrings, brooch, ring, bracelet, and sometimes a tiara. Parures were introduced in the 18th century.

PASTE – Glass made to resemble gem materials, which may be moulded, faceted, carved, etc.

PAVÉ – Front or surface of ornament is covered with stones held in position by bead-setting. The article will look like it has been paved with stones.

PAVILLION – The portion of the stone below the girdle.

PEARL – A calcareous concretion of calcium carbonate and organic matter secreted by a mollusc in response to an irritation. Layers on nacre and conchiolin are secreted concentrically around a centre or core in response to an irritant. Natural pearls are formed when an object such as a grain of sand gets in between the inner layer of the shell and the mantle of the oyster. Cultured pearls are produced exactly the same way except that the irritant is introduced into the oyster by human means. Imitation pearls are simply glass beads with a thin coating of synthetic pearl essence. The beauty of pearls comes from the nacre or iridescent outer layers. The value of pearls is based on colour, lustre, translucency, texture, shape and size. A thick coating of nacre is essential for durability and for the utmost in beauty in a pearl.

PERIDOT – A variety of chrysolite. It is the gem of variety of olivine. The colour is generally a warm olive or yellowish green. The main source is St. John's Island in the Red Sea.

PEWTER – There are no government regulations for pewter standards but there is an industry standard devised by the American Pewter Guild, assisted by the American Society of Testing and Materials. Guild members honour it as law. Their pewter is 92% tin, 7% antimony and 1% copper. Because high quality pewter takes a fine polish, it is not being used for some jewellery, especially pendants. Some "pewter like" metal is now being used to manufacture lighter weight; sand cast aluminium - based products and is sold under such names as Arm tale, Ameralloy and International Crafts Metal.

PIETRA DURA – Polished gem materials set in a ground of (usually) black marble to form a design or motif.

PINCHBECK – An early 18th century alloy of copper and zinc (9 parts zinc and 48 parts copper) invented by Christopher Pinchbeck. Another formula consisted of 83 parts copper and 17 parts zinc. It looks like gold, wore well and maintained its colour. Now collected, not as a substitute for gold, but for its antiquity.

PIQU – Diamonds with eye visible inclusions.

PIQUE – Gold and silver worked into tortoiseshell in various designs.

PLATINOID – An alloy consisting of copper, nickel and zinc, used now mainly for forming electrical coils and standards.

PLATINUM – It does not tarnish. It is lighter, harder and stronger than silver which it superseded as a setting for diamonds making finer intricate settings possible. Platinum is considered the ideal material for diamond settings. Platinum was first hallmarked in the UK in 1975.

PLIQUE A JOUR – Enamel work in which the enamel has no background (it is confined within un-backed metal frames) and resembles the effect of a stained glass window. The design is outlined in metal and filled with a variety of collared, transparent/translucent enamels. In this process there is no backing behind the enamel, so the effect is similar to stained glass windows. A technique used widely in Art Nouveau jewellery and of which Rene' Lalique' is considered the master.

PLUM GOLD – Gold products, which when marked with a quality stamp, must assay at that level. For instance, a ring stamped 18ct must assay 75% gold including solder and ornamentation.

POINCON – Refers to French hallmarks.

POSY RINGS – Those which have a "posy"/ "rhyme", or motto engraved on the inner side. They were popular in the 16th and 17th centuries.

PRECIUM – A palladium - silver alloy developed for jewellers by Handy & Harman. Used both as a casting alloy and a wrought alloy.

PRINCE ALBERT – Refers to a man's watch chain, single or double width, which was popularised by Prince Albert.

PROVENANCE – Documented history of a piece including origins and important owners, etc.

QUARTZ – Quartz is a silicon oxide (SiO2) with the various colours being derived from metallic oxides. Varieties include, Amethyst, Citrine, Smoky and Cairngorm.

RADIANT CUT – Based on the emerald cut, it features 70 facets with step cut facets above the girdle and triangular facets below.

REBUS – Often used on intaglios for seal purposes. Words are represented by objects or symbols, the names of which, when sounded in sequence, give the solution.

RED EMERALD – A ruby - red beryl, a crimson counterpart of emerald, was discovered in Utah and reported to the 36th annual Conclave of the American Gem Society held in Cincinnati in 1970. It is the first true red beryl ever reported.

REGARD RING – A ring set with a row of small stones of different kinds, the initial letters of which spell a word, for example, to spell "regard", the stones could be: Ruby, Emerald, Garnet, Amethyst, Diamond.

REPOUSS – The raising of a pattern in relief on metal by beating from the under side.

ROLLED GOLD – Fusing gold to a base metal with heat and pressure produces rolled gold.

ROMAN FINISH – The dull yellow effect on a plain or modelled surface gained by depositing fine gold on a roughened surface. It is softer than the bright finish, and was obtained by early jewellers by chemical action on the article itself by means of which the alloy of silver and copper was eaten out on the surface and pure gold left.

ROSE CUT – A method of cutting stones dating from the mid-seventeenth century. The stone has a flat base and rises to a faceted pointed top. The diamond is cut with 24 triangular facets in the shape of a hemisphere. In all seven principal variations of the rose cut the facets are hexagonally arranged and the base of the stone is flat.

ROSE GOLD – A gold of any karat alloyed with copper or copper and silver. To give a rose colour or hue.

ROUND BRILLIANT CUT – A standard modern round cut for stones, having 58 facets (33 facets on the crown and 25 facets on the pavilion if a culet is present).

RUBY – From the Corundum family, the red variety being ruby and the blue, sapphire. With the exception of the diamond, corundum is the hardest of the gemstones on the Mohs scale scoring a 9. Ruby is derived from the Latin "Ruber" meaning red. It has long symbolised eternal devotion and romantic love.

SAPPHIRE – Part of the Corundum family. Sapphire comes from the Persian "Saffir", or the Greek "Sapphiros". Blue is the best-known colour but it can be found in all colours of the spectrum.

SARD – Identical to cornelian except for the colour which is a deep brownish red. It was used by the Greeks and Romans for engraved intaglios and seals; not used much now for jewellery. The word comes from the Greek, Sardios - a Sardian stone from Sardeis, capital of Lydia.

SAUTOIR – A very long narrow necklace (beads or chain), often having a tassel or ornament at the bottom.

SCARF RINGS OR SLIDES – Like large finger rings, but flattened instead of circular, with a gadget inside the back which held the scarf securely. Popular in the Edwardian period.

SEAL – Carved with an intaglio but with design reversed so that it is readable when impressed in wax, etc.

SEED PEARL – A natural pearl 2mm or less in size.

SHAKUDO – Shakudo (gold and copper) is the legendary japanese metalwork which was first used on samurai swords until the japanese government prohibited the wearing of samurai swords in 1877. Craftsmen started to supply the western world with stunning pieces which were then mounted into items of jewellery.

SILVER PLATE – Actually electro - plate or deposit of silver electrolytically on a base metal.

SINGLE CUT – A round stone with just 18 facets, top and bottom used only on very small stones.

SPINEL – It is frequently called "Balas Ruby", a term derived from Badakshan, the name of the district in Afghanistan which is said to have been the source of the finest stones in mediaeval times. Spinels are often mistaken for rubies, perhaps the most famous of these is the "Black Prince"s Ruby" in the Imperial State Crown which is actually a red spinel and the "Timur Ruby" in the private collection of the Queen.

STAR SET – A gem is deeply set, with its table scarcely rising above the surface of surrounding metal, having rays engraved as though coming from the gem, which then appears as a star.

STEP CUT – Horizontal, layered facets, as in emerald cut, also called trap-cut.

STERLING – An alloy of 925/1000 fine silver with a permitted tolerance of 4/1000ths for an article made without solder or 10/1000ths if it includes solder.

STYLE – A piece described (i.e.) as "Georgian style" has the appearance of a piece made during that period, but was made at a later date.

SYNTHETIC – A man-made material with essentially the same optic, chemical and physical properties as its natural counterpart, but completely artificial.

SYNTHETIC DIAMONDS – On May 28, 1970 General Electric Company announced that they had produced gem quality synthetic diamonds. Their costs to date far exceed that of natural stones. G.E. first produced industrial diamonds in 1954. These are used for abrasives, drilling and wire - drawing.

TABLE – The large horizontal facet on the top of a faceted stone.

TAILLE D'EPERGNE – A kind of enamelling, the reverse of CHAMPLEVE, as the ornamentation is simply engraved and then filled with enamel.

TANZANITE – The deep blue variety of zoisite was first discovered in Tanzania in 1967 to which Tiffany & Company gave the trade name "Tanzanite". It has a hardness of 6 on the Mohs scale. Most crystals occur in a variety of colours, usually brownish or greenish and are heat treated to produce the deep blue colour. This treatment is permanent and is a duplication of the natural process, but accelerated by man.

TESTED – A metal that has been acid tested to ascertain that it is gold or silver, etc., and if such further tested to give a near accurate assessment of gold content or silver content.

THUMB RINGS – Worn from the 14th to the 17th century.

TIFFANY & CO – Tiffany & Co is an American jewellery and silverware company founded by Charles Lewis Tiffany and Teddy Young in New York City in 1837 as a "stationery and fancy goods emporium". The store initially sold a wide variety of stationery items, and operated as Tiffany, Young and Ellis in lower Manhattan. The name was shortened to Tiffany & Co in 1853 when Charles Tiffany took control, and the firm's emphasis on jewelry was established. Tiffany & Co. has since become a global brand, famous the world over.

TOPAZ – "Topaz" comes from a Sanskrit word meaning heart of fire. According to Pliny, the gem was named for the island of Topazus in the Red Sea, where the stones were first found. Topaz is very hard, being 8 on the Mohs scale, with a high cleavage.

TORSADE – Any strands of jewellery that can be worn twisted.

TOURMALINE – The name is derived from the Singhalese word "turamalli" which was applied for the first time when some of these stones were brought from Ceylon to Amsterdam in 1903. They may occur in pink, red, yellow, blue, brown, black or green. Tourmaline does not tend to break or chip easily. The hardness is 7 to 7.5 on the Mohs scale.

TREMBLANT – A section of a piece of jewellery mounted on a tiny spring to allow it to tremble when worn.

TURQUOISE – A beautiful opaque stone which gives its name to the colour. It was used extensively in jewellery at the end of the 18th century and during the 19th. Named Turkois by the ancient Venetians. The best turquoise is medium blue and even in colour. It is fairly soft being only 6 on the Mohs scale.

UNION PIN – A pin in two parts, one part having a hole or socket into which the point of the actual pin fits, so that it is joined into one piece.

VAN CLEEF & ARPELS – Van Cleef as we know it today was founded in 1906 by Alfred Van Cleef (a young Dutch lapidary) and two brothers Julien and Louis Arpels. Their first shop in the Place Vendome at number 22, where they are still located today was designed to attract a wealthy clientele and led to immediate success. Their clients included celebrities such as Marlene Dietrich, Maurice Chevalier and Eva Peron for whom a diamond and sapphire Argentinian flag brooch was designed in the early 1950s. The company also designed the tiara worn by Grace Kelly when she became Princess Grace of Monaco in 1956. For the coronation of Farah Pahlavi, the former Empress of Iran, Van Cleef & Arpels received an order to design and build a crown in 1967, which weighed four pounds and took them six months to make. The firm's jewellery is characterised by its fluidity, graceful curves, colour, and the sense of movement given in the design or the moving parts integrated into the piece. They are the creators of the 'Serti Mysterieux' the invisible setting, a setting still used today on important pieces.

VERMEIL – Sterling silver base with requisite quantity of gold applied. Fraction may indicate ration of gold content to total weight. In the past it has been used to mean 'gold on sterling'.

VINAIGRETTE – A small box made of gold, silver, etc., with perforations on the top for holding aromatic vinegar, smelling salts, etc.

WALDEMAR CHAIN – Worn across the vest between the two pockets. On one end there is a swivel for the watch and on the other a spring ring for a knife, cigar cutter, pencil or other trinket.

WATCH CHAIN – Goes to one pocket of a waistcoat and has a bar and drop chain for attaching a charm.

WHITE GOLD – White gold is produced by alloying copper, nickel and zinc with gold, to give it the white colour.