C

Cabochon

A stone that has been polished into a dome shape with no facets. The cut is used primarily to create and enhance phenomenon in gems such as star sapphires.

Calibrated

Calibrated gemstones are mass-produced and come in certain ‘calibrated sizes’, for standard mass produced gemstone settings. If a gemstone does not fit a standard mount, one will need to be custom made.

Calibré

A stone specially cut to fit a particular mount, rarely used in modern jewellery due to the expense.

Carat

A weight measurement of a gemstone or gold. The term is derived from the ancient used of carob seeds to balance scales when selling amounts of gold or gemstones. The term is often shortened to ‘ct’.

For diamonds and gemstones, one carat is equal to 0.2g. Read more about The Four C’s.

For gold, the carat is expressed as a part of 24, 24 carat being pure gold. For example, 9 carat gold is 9 parts pure gold and 15 parts alloying metal such as copper.

Cartier

A renowned French jewellery house founded in 1847 by the jeweller Louis-Francois Cartier. The maison Cartier created the first practical wristwatch, ‘Santos’ in 1904. They have a long history of creating special pieces for royalty and celebrities all over the world, so much so that The Prince of Wales, the Future King Edward 7th declared Cartier the ‘jeweller to kings, king of jewelers.’

Ceylon

Used in the trade (though decreasingly) in relation to gemstones when describing the origin of sapphires from Sri Lanka.

Channel Set

A method of setting whereby stones are set and secured between two ‘channels’ of metal side by side in a row.

Chatoyancy

A phenomenon in a gemstone known as ‘Cat’s Eye Chrysoberyl.’ This is created from a number of similarly aligned inclusions in a stone that when cut in a cabochon creates a defined streak of light across the surface. Read more

Chenier

A decorative enhancement to a ring, in the shaped of a metal tube that was usually added under the shoulders of the ring – particularly used in antique pieces.

Citrine

A pale yellow to brownish orange variety of quartz, rare in nature. Its colour is sometimes confused with topaz. It is an attractive alternative not only for topaz but for yellow sapphire. Read more

Clarity

A term used to describe the severity of the internal and external inclusions in a gemstone. See The Four C’s for further information.

Claw Set

A method of setting whereby stones are set and secured between a number of ‘claws’, usually four, six or eight. The method of setting was popularised by Tiffany & Co. in the late 1880s, and allows more light to pass through a gemstone than other settings. Sometimes referred to as prong set.

Cleavage

This is a plane in gemstone along which a clean break may occur. The term ‘feather’ is often used to describe an inclusion in a diamond which is a small break along such a plane.

Closed Back

A method of setting whereby the back (or bottom) of the stone is enclosed.

Collet Set

A method of setting gemstones whereby stones are set and secured by a band of metal that goes all the way around the girdle of the gemstone.

Colour

The diamond colour grading scale ranges from D to Z. See The Four C’s for more information.

Colour Zoning

Areas of different colour in a gem caused by variations in grown conditions. Examples are a bi-colour or watermelon tourmaline, or ametrine (a type of quartz).

Comfort Fit

The name for a band that is slightly curved on the inside to provide extra comfort against the finger.

Crossover Ring

A term to describe any style of ring where the shank either splits and crosses over each other or where the two ends of the shank bear away from each other and lay side by side. Crossover rings are usually diamond set. See a selection of our crossover rings.

Crown

The top part of a gemstone above the girdle.

Culet

The smallest facet of a diamond, the culet is located at the very bottom of the stone. If the diamond ends in a point, the diamond grading report will show a value of ‘None’ for the culet designation. This small facet was originally intended to protect the diamond’s pavilion, although today’s settings are usually strong enough to render it unnecessary.

Curb Chain

A type of chain created from connected flat oval shaped links.

Cushion Cut

First introduced to the jewellery market in the early 1800’s, the cushion cut diamond is rich with diamond history. Cut into a square or rectangular shape with rounded corners and sides, it’s considered by many to be a more vintage version of the round cut diamond.

Cut

One of the most defining characteristics of a diamond is its cut. While high grades of color, clarity, and carat weight affect a diamond, it’s the cut that determines the symmetry of the stone’s facets, its overall proportions, and its ability to reflect light. An expertly cut diamond will achieve high levels of brilliance, sparkle, and durability. For more information and cut types, see The Four C’s.