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The Spark of Confidence

Glossary

Pavilion

Lower part, or ‘bottom half’, of a diamond below the girdle.

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Pavilion Angle

Angle measured between the girdle plane and the pavilion main facets.

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Pavilion Depth

Distance in millimeters or percentage from the girdle to the culet.

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Pavilion Depth Percentage

Pavilion depth expressed as a percentage of the diameter. Pavilion depth is an extremely important proportion to the brilliance of a diamond; diamonds with a pavilion that is too deep will have a nailhead, while diamonds with a pavilion that is too shallow or flat will have a fish eye.

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Pavilion Main Facets

Kite-shaped facets clustered from the culet and extending to the girdle.

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Pear Cut

Diamond cut or shaped into the outline of a tear-drop or a pear, with a rounded head tapering to a point.

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Phosphorescence

Phenomenon that causes some diamonds to continue “glowing in the dark,” after a light source is removed. Phosphorescence is much more common in synthetic diamonds than in natural diamonds.

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Pink Diamond

A coloured diamond with a natural pink body colour. Pink must be the predominant colour, but it may be modified by shades of purple, orange, and yellow. The colour in natural pink diamonds is created by irregular crystal structure. Some pink coloured diamonds with sufficient saturation fall into the valuable fancy pink colour category of diamonds.

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Pinpoints

Very tiny diamond crystal inclusions that are too small in size to distinguish their individual shapes. One pinpoint looks like a small “dot” under 10x magnification. Clusters of pinpoints create a cloud.

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Pit

Type of diamond blemish that appears as a tiny opening or indentation on the surface of a diamond. Large pits are called cavities. Pits affect the polish grade of a diamond.

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Pitted Facet

Diamond facet with numerous pits. Pitted facets affect the polish grade of a diamond.

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Plotting Diagram or “Plot”

Diagram of the approximate relative size, location, and type of internal inclusions and external blemishes of a diamond. A plotting diagram is often used for identifying a particular diamond.

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Point

Term for one hundredth of a carat. For example, a fifteen-point diamond weighs 0.15 carats. It could also be called a fifteen “pointer”.

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Polish Grade

Qualitative analysis of the overall surface condition of a diamond. The quality of polish is determined by the care put in by a polisher when finishing a diamond, and is important to the brilliance and scintillation given off by a diamond.

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Polish Lines

Lines left on the surface of the diamond which are visible under magnification, normally removed during the final diamond polishing process. Polish lines can affect the polish grade of the diamond.

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Polished Girdle

Describes the girdle of a diamond that has been fully polished smooth and clear around the entire perimeter. Step cut diamonds such as emerald cut and baguette cut diamonds usually have a polished girdle, and some brilliant cut diamonds may have polished girdles as well.

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Princess Cut

Diamond cut or shaped into a square or rectangle. Princess cuts combine features of both step cut and brilliant cut diamonds.

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Proportion Grade

Qualitative analysis of the overall proportions on a round brilliant cut diamond. Fancy shaped diamonds are not proportion graded; unlike round cut diamonds, there is no defined range of proportion standards for fancy shapes.

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Proportions

Relations between the dimensions and angles of a finished diamond. Examples of specific proportions are table size, depth percentage, and crown angle. Proportions are extremely important to the beauty, brilliance, and life in a diamond. Click here to learn more about proportions on a diamond grading report.

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latest news

Tuesday 25 April, 2017

CHRISTIE’S TO OFFER 92CT. PENDANT

A 92.15 carat diamond pendant worth up to $20 million will lead Christie’s Magnificent Jewels auction in Geneva next month.

Thursday 20 April, 2017

GRAFF UNVEILS 105-CARAT D-FLAWLESS DIAMOND

Graff Diamonds has unveiled the 105.07 carat D flawless pear shaped diamond, it has named the Graff Vendôme after its new retail outlet at Place Vendôme in Paris.

Monday 10 April, 2017

LETSENG MINE YIELDS 114CT. DIAMOND

Gem Diamonds has found a 114-carat rough diamond at its Letšeng mine in Lesotho, the miner reported Friday.

Tuesday 4 April, 2017

SOTHEBY'S SELLS 59.6 CARAT PINK FOR $94.2 MILLION AUD

Steinmetz Diamonds owned by Israeli billionaire Benny Steinmetz, spent two years cutting and polishing the Rough diamond. Which was mined by De Beers in Botswana, Southern Africa.

Thursday 30 March, 2017

DE BEERS, LUK FOOK TO CO-BRAND GRADING REPORTS

Tuesday 21 March, 2017

59.6 CARAT VIVID PINK DIAMOND

Sotheby's plans to auction the famous "Pink Star" diamond an internally flawless, fancy vivid pink stone at its sale in Hong Kong on April 4.

Wednesday 8 March, 2017

GIA FINDS SIGNIFICANT UNDISCLOSED SYNTHETICS

The Gemological Institute of America (GIA) recently uncovered an unusually large number of undisclosed synthetic diamonds mixed in with natural melee diamonds, the lab confirmed with Rapaport News on Monday.