Glossary & Picture Library, learn

The Spark of Confidence

Glossary

Table

Large flat facet centered on the crown of a polished diamond.

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Table Size

Measure of the table width expressed as a percentage of the diameter. Table size is a proportion important to the balance between brilliance and dispersion.

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Tapered Baguette Cut

Diamond cut or shaped into a triangle with one corner cut off, and rows or steps of elongated facets running parallel to the girdle on both the crown and the pavilion. It is a modified version of a standard baguette cut.

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Tone

Degree or depth of colour in terms of lightness or darkness. The tone of a coloured diamond can range from very pale to very dark; it is the degree to which the colour of a diamond approaches white on the pale end, and black on the dark end.

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Toughness

Measure of brittleness, or resistance to fracture and breaking. Diamond has very good durability, but due to its directional hardness diamonds have certain planes of weakness along which they can split or break. Toughness and hardness together determine the durability of diamond.

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Transparency

Degree to which a diamond transmits light, directly relevant to the cloudiness or haziness of the actual diamond material, and the quality of the crystal. Click here to learn more about transparency and the DCLA Transparency Grading System.

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Treated Diamond

Diamonds that are artificially enhanced, to improve either colour or clarity. These treatments fundamentally alter the diamond from its natural state, and therefore need to be fully disclosed. Click here to learn more about treated diamonds.

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Trigon

Triangular shaped natural, with very fine triangular concentric lines. Trigons, when present, are a definitive indicator of natural diamonds.

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Trilliant

Diamond cut or shaped into a triangle, sometimes with curved sides.

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Twinning Line

Type of diamond inclusion that appears as a line or ribbon of pinpoints, tiny feathers, clouds, and crystals. Twinning lines are created where two rough diamonds have grown together in the earth under extreme heat and pressure.

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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.