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Jewellery & Watches Glossary

4 Cs

Standards used by experts to measure and evaluate diamonds. The four Cs are cut, clarity, colour, and carat.

American Gem Society Laboratories: Gemological laboratory founded in 1978 and based in Las Vegas, Nevada.
Akoya cultured pearls

Saltwater cultured pearls from China and Japan. They have higher luster than freshwater pearls. Colour ranges from cream to white/pink. The average-priced pearls are usually 6 to 8.5 mm.

Process of reducing a metal’s purity by mixing it with other metals.

Durable metal resistant to tarnish, rust, and corrosion.
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Type of timepiece with hour and minute hands.

Type of timepiece with analog and digital readout.

Estimated retail value of an item.
Asscher cut

Type of square diamond cut featuring dramatically cut corners.

Dense, synthetic resin used for jewellery during the Great Depression. It can be molded, carved, or inlaid into another form. Also called Catalin.
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Gemstone associated with the month of someone’s birth.

January: Garnet
February: Amethyst
March: Aquamarine
April: Diamond
May: Emerald
June: Pearl and Moonstone
July: Ruby
August: Peridot
September: Sapphire
October: Opal and Tourmaline
November: Yellow Topaz and Citrine
December: Blue Topaz and Turquoise

Victorian-era metal chain style identified by rectangular links of folded metal resembling small books.

Carving or engraving on a shell or stone, usually portraits of women, where the design comes above the surface, in relief.

One of the 4 Cs. Measurement of a diamond’s weight. As carat weight increases, diamond value increases.
1 Carat = 100 Points = 200 milligrams
Carbon fibre

A dark coloured (dark grey or black) and tough material used for watch casings and dials.
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Dense, synthetic resin used for jewellery during the Great Depression. It can be molded, carved, or inlaid into another form. Also called Bakelite.

Flammable plastic derived from natural plant fibre. Celluloid was first manufactured in the late 1800s and used for a variety of objects, including hair accessories.

Official document issued by third-party gemological labs listing specifics about an individual gem (at least the 4 Cs) independent of market value. It can include information about diamond quality, validation that a diamond is organic, and the serial number on the girdle of laser-inscribed diamonds.

A stopwatch or metre feature on a watch that measures time elapsed. Chronographs can also come in a 'split second' format to measure two time segments simultaneously or consecutively.

One of the 4 Cs. Clarity describes the amount and severity of inclusions found in a diamond. Flawless diamonds are very rare and more expensive.
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Clarity-enhanced diamonds

Diamonds that have undergone treatment to remove visible imperfections. In the clarity enhancement process microscopic amounts of material similar to a diamond are inserted into the flaws. Light then flows freely through the diamond eliminating the imperfection from view. Because the material is used in small quantities, it does not add to the weight of the diamond

One of the 4 Cs. Colour describes the trace amounts of yellow found in diamonds that appear white. Diamonds with the most value fall in the colourless range.
Colour-enhanced diamonds

Diamonds that have undergone treatment to alter or heighten colour. A number of procedures can change a diamond's natural colour, including irradiation using high-energy particles. Depending on resulting colour, “after” coloured diamonds can be more expensive than their untreated counterparts. The safe irradiation process does not affect any aspect of the diamond other than colour.
Conflict diamonds

Diamonds sold to fund wars and purchase weapons. Conflict diamonds originate in countries such as Angola, Sierra Leone, and the Democratic Republic of Congo. Since 1998, organizations such as Amnesty International have been working to stop the sale of conflict diamonds.
Costume jewellery

Jewellery made of a glass, plastic, or a non-precious base metal, often plated with a precious metal, and synthetic stones.
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Top portion of a diamond.
Cubic Zirconia (CZ)

Synthetic gemstone created from Zirconium Oxide. CZ bears a strong resemblance to diamonds, but does not contain the same impurities. Professionals (and some laymen) can tell the difference between diamonds and CZ by looking at a stone’s facets and clarity under magnification.
Cultured pearls

Pearl produced when a person introduces a small object into a pearl-producing mollusk. Kokichi Mikimoto first began pearl cultivation in the early 1900s. The four common types of cultured pearls are Freshwater CulturedPearls, Akoya Cultured Pearls, Tahitian Cultured Pearls, and South Sea Cultured Pearls.

One of the 4 Cs. Describes the shape, grade, depth, and polish of a diamond. A well-cut diamond reflects light to maximize a stone's brilliance.
Cut depth

How deep a stone is cut in relation to the size of its table.
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Cut grade

Describes cut of a diamond by its shape or outline and the facet arrangement pattern.
CVD diamonds

Chemical Vapor Deposition: The CVD process mixes carbon in its gas form with hydrogen and methane gas. When heated, the mixture pours onto diamond kernels that slowly grow into diamonds.

Valuable gemstone made of pure carbon and the hardest naturally occurring substance on Earth.
Diffusion treatment

Process of enhancing apparent gemstone colour by treating the gem with cobalt, beryllium, or other elements. The process only changes the surface of a stone and scratches can reveal lighter hues underneath.

Timepiece providing time information using numerical digits. Usually uses an LCD display.
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Mock gemstone produced by gluing two different materials together to create the illusion of a more valuable gemstone. Common in the Victorian era was the garnet and glass doublet, which consisted of a red garnet top glued to a coloured glass bottom.

European Gemological Laboratory USA: Independent gemological lab based in New York. Although a few labs carry the EGL name, only EGL-US certificates are permitted in the United States.

Green-coloured beryl gemstone. Colour ranges from yellow-green to blue-green with pure green stones holding the most value. Emeralds lend themselves to elaborate carving and inscription and are typically given as May birthday gifts and 20th, 35th, and 55th wedding anniversary gifts.

Flat, polished surface on a cut gemstone.
Fancy diamonds

Coloured diamonds available in deep yellow, pink, green, orange, blue, red, and black. Also known as Z+ diamonds.
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Ornamental gold or silver wire twisted into intricate patterns and fused into place.
Fine jewellery

Jewellery made of precious metals. Fine jewellery may contain precious or semi-precious stones.
Freshwater cultured pearls

Affordable cultured pearl farmed from freshwater lakes and rivers in China. Size ranges from 3.5 to 7.0 mm. Usually white in colour, freshwater cultured pearls sometimes have a pink or rose tint.

Hard and lightweight black stone formed from fossilized coal. It was commonly used in mourning jewellery during the Victorian period. Also known as jet.

Mineral cut and polished for use in jewellery.
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Gemological Institute of America: Gemological lab considered the gold standard of diamond graders. Established in 1931, the not-for-profit GIA has a number of worldwide locations.

Area grasped by prongs when a diamond is mounted into a setting. Where crown and pavilion meet.

Highly-malleable metal used in jewellery. It comes in three colours: yellow gold, white gold, and rose gold.
Gold filled

A layer of at least 10-karat gold bonded to the surface of a support metal. The karat gold must be at least 10% of the total weight. Also called gold overlay.
Gold leaf

A very thin layer of gold is applied by hand to the surface of an item.
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Gold overlay

A layer of at least 10-karat gold bonded to the surface of a support metal. Karat gold must be at least 10% of the total weight. Also called gold filled.
Gold plate

Similar to overlay, gold content may be as little as 5% of an item’s total weight.
HPHT diamonds

High Pressure High Temperature Diamonds: Diamonds created by simulating geological conditions that produce organic diamonds. A small nucleus providing the core of the diamond is placed on a surface of carbon and extreme pressures and temperatures are applied. The carbon then forms into a diamond crystal.

Unique colour of a gemstone. Almost all gemstones have some shades of other colours. Gemstones with the most value present the purest hue: red rubies, green emeralds, and either blue or pink sapphires. Gemstone certificates describe hue and mention any tints or variations of the main colour.

International Gemological Institute: Gemological laboratory that has graded diamonds and gemstones since 1975.
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Tiny mineral traces or flaws.

Process of coating jewellery with lacquer.

Hard and lightweight black stone formed from fossilized coal. It was commonly used in mourning jewellery during the Victorian period. Also known as gagate.

Jewellers Vigilance Committee: Non-profit trade association that advocates legal compliance and ethical practices and acts as a recognized legal arm of the jewellery industry. JVC mediates disputes within the trade as well as disputes between industry members and consumers.

Measurement of gold’s purity. Pure gold is 24 karats, but 24K gold is too soft to securely hold a stone. So gold is alloyed with other metals such as silver, copper and zinc to make it sturdier. Typical measurements for alloyed gold are 18K (75% gold), 14K (58.3% gold) and 10K (41.6% gold). In the United States, metal that is less than 10K cannot legally be sold as gold. However, a lot of vintage jewellery falls in the 9K to 10K range.
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Kimberly Process

Set of international standards, launched in January 2003, that attempts to certify international diamonds and identify the origin of each diamond in an effort to halt the trade of conflict diamonds.
Lace pin

Small brooches designed to fasten lace scarves in the late Victorian and Edwardian eras.
Laser drilling

Method of enhancing a diamond by removing inclusions with a laser. Laser drilling provides permanent inclusion removal and does not affect the diamond's strength.

Liquid Crystal Display: A low-power monitor used to display time and special features on a digital watch.

Description of a pearl’s shine. The higher the luster, the greater the pearl's value.
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Bar of metal used to size rings.

Small pictures or decorations composed of tiny colourful tiles made of stone, glass, or other materials.

Diamond look-alike created from silicon carbide. Moissanite has properties similar to diamonds including extreme hardness, brilliance, and inclusions. Because of these close similarities Moissanite often costs more than CZ.
Moonphase indicator

Watch display indicating the phase of the moon through an image on a rotating disk.
Mourning jewellery

Subdued jewellery made of jet or black glass and metal with a Japanned finish. Queen Victoria popularized mourning jewellery after her husband, Albert, died in 1861.
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Soft coating of calcium carbonate that pearl-producing mollusks produced around foreign objects introduced into their bodies.

Bottom portion of a diamond.

Organic gemstone formed when a small foreign object gets introduced into the body of a pearl-producing oyster or mussel. The organism produces a soft coating of nacre around the object to form the pearl. Since naturally occurring pearls are rare, cultured pearls are most often used in jewellery.

Hypoallergenic metal with high durability, heavy weight, high value, and minimal threat of tarnishing.

Surface smoothness of a diamond or gemstone. Also describes the quality of polishing, the process of removing excess parts stone to expose its facets.
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Precious metal

Term referring to gold, silver, and platinum.

When a wearer presses a button, watches with a repeater announce time through a series of chimes.

Hard, white metallic element used in platinum alloys.
Ring sizer

Series of rings in different sizes used for determining a person’s ring size.
Rose Gold

Gold alloyed to bring out deeper pink accents.
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Gemstone with hue ranging from orange-red to purple-red. Used as the birthstone of the month of July, rubies are also given as presents for 15th and 40th year anniversaries.

Gemstone with hue typically ranging from blue-green to blue-purple. Sapphires can also come in other colours including colourless, white, yellow, orange, pink, brown, and black. They make great gifts for September birthdays as well as 5th and 45th wedding anniversaries.

Purity of colour throughout a gemstone. A “strongly saturated” gem free of gray or brown hue has a higher value than a stone with lower saturation.

Narrow band of metal that holds a stone in place in a piece of jewellery. It surrounds the girdle or perimeter of a diamond or gemstone.
Signed jewellery

Process of cutting or embossing a sheet of metal with a mark or pattern, in relief, using a punch or die. Typically found on mass-produced jewellery and medallions. Also called stamped jewellery.
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Malleable and abundant metal that tarnishes easily and requires care and cleaning more often than other precious metals.
Simulated gemstones

Crystals cut to resemble diamonds. They do not have the strength or sparkle of natural diamonds.
South Sea cultured pearls

Large (up to 13 mm) cultured pearl farmed in Australia, Indonesia, and the Philippines. Colour ranges from white to black and they can be expensive depending on luster.
Stamped jewellery

Process of cutting or embossing a sheet of metal with a mark or pattern, in relief, using a punch or die. Typically found on mass-produced jewellery and medallions. Also called signed jewellery.
Sterling silver

Typically what people mean when they talk about silver jewellery, sterling silver is 92.5% silver and 7.5% copper. Jewellery should be marked "sterling," "925," or "ster."
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Balance of gemstone facets.

Flat top of a cut diamond.

A scale located around the rim of a watch dial that, when used along with the chronograph, allows measurement of average speed through the calculation of time and a pre-measured distance.
Tahitian cultured pearls

Large (11 to 13 mm) black to grayish-green coloured cultured pearl farmed on the volcanic atolls and reefs of Tahiti. Scarcity and a unique look make Tahitian pearls more expensive than other cultured pearls.
Telemetre scale

Scale that measures distance between a watch wearer and an object that generates a visible signal and a loud noise (such as a fired cannon or electrical storm).
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A strong, white metal that has benefited from recent trends in sports watches which require sturdier materials. Titanium is 30% stronger than steel, corrosion resistant, and very light. However, unless treated with a protective shield, it can scratch easily.

Depth of gemstone colour, from colourless to black, described on a scale of light, medium, and dark. The most valuable stones range from medium-light to medium-dark.

Small but costly mechanism within a mechanical watch that helps eliminate potential time errors.
Water resistance

Measurement of a watch’s resistance to water measured in feet, metres, or atmospheres (ATM). Resistance ranges from zero to over one thousand metres in depth.

• 30 metres: Splash proof
• 50 metres: Can be worn in the shower
• 100 metres: Can be worn swimming
• 200 metres: Can be worn scuba diving
White gold

Virtually non-tarnishing gold with a shiny silver hue that makes it look like platinum.
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World time

Watch feature that indicates time in all time zones around the world simultaneously. The dials or face display the names of cities around the world in each time zone and can be adjusted to read the time in that zone.
Yellow gold

Non-corrosive and sturdy gold. Diamonds set in yellow gold benefit from colour contrast and slightly tinted stones can appear brighter.
Z+ diamonds

Coloured diamonds available in deep yellow, pink, green, orange, blue, red, and black. Also known as fancy diamonds.
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