The 4Cs: Clar­ity, Colour, Cut and Carat Weight

Adorn - - GEM FACTS -


Di­a­monds come in many colours. Those rang­ing from colour­less to light yel­low and brown fall within the nor­mal colour range. Within that range, colour­less di­a­monds are the most valu­able and set the stan­dard for grad­ing and pric­ing.


Clar­ity char­ac­ter­is­tics re­fer to di­a­mond’s in­ter­nal fea­tures, called in­clu­sions, and sur­face ir­reg­u­lar­i­ties, called blem­ishes. Clar­ity is the rel­a­tive ab­sence of in­clu­sions and blem­ishes. Flaw­less di­a­monds are very rare and com­mand top prices.


Cut refers to the pro­por­tions, sym­me­try and pol­ish that ef­fects how a di­a­mond’s facets in­ter­act with light. Di­a­monds with dif­fer­ent pro­por­tions and good pol­ish make bet­ter use of the light, and will be bright, colourful and scin­til­lat­ing.

The term “cut” can also de­scribe a fash­ioned di­a­mond’s shape. Shapes other than the stan­dard round bril­liant are called fancy cuts. The best known are the mar­quise, princess, pear, oval, heart and emer­ald.

Carat Weight

Di­a­mond size is mea­sured by weight in terms of met­ric carats. One carat is two-tenths (0.2) of a gram. Di­a­monds are weighed to a thou­sandth (0.001) of a carat and then rounded to the near­est hun­dredth, or point. Frac­tions of a carat can mean price dif­fer­ences of hun­dreds – even thou­sands – of dol­lars, depend­ing on di­a­mond qual­ity.

Large di­a­monds are rarer than small di­a­monds. So al­though a 1-carat di­a­mond weighs the same as four 0.25-carat di­a­monds, if all the other qual­ity fac­tors are equal, the larger di­a­mond is worth much more than the sum of the four smaller di­a­monds.

Spe­cial Notes

Many di­a­monds emit a vis­i­ble light called flu­o­res­cence when they’re ex­posed to ul­travi­o­let (UV) ra­di­a­tion. Blue is the most com­mon flu­o­res­cent colour in gem-qual­ity di­a­monds. In rare in­stances, flu­o­res­cence can be white, yel­low, or­ange or other colours. Strong blue flu­o­res­cence can make a light yel­low di­a­mond look closer to colour­less in sun­light. If the flu­o­res­cence is too strong it can make the stone look cloudy or “oily,” which can lower the value of the di­a­mond.

How to Care for Di­a­monds

Di­a­monds are the hard­est ma­te­rial on earth – 58 times harder than any­thing else in na­ture – but any stone, in­clud­ing a di­a­mond, will break if it’s hit hard enough in the right place.

Warm wa­ter and mild soap with a tooth­brush is a safe way to clean di­a­mond jew­ellery. Di­a­monds can also be safely cleaned with lint-free cloths and commercial jew­ellery clean­ing so­lu­tions.

By Ni­rav Modi

Sari neck­lace.

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