Cut

The cut of a diamond determines its brilliance. There is no single measurement of a diamond that defines its cut, but rather a collection of measurements and observations that determine the relationship between a diamond's light performance, dimensions and finish. Most gemologists consider cut the most important diamond characteristic because even if a diamond has perfect colour and clarity, a diamond with a poor cut will have dulled brilliance.

The width and depth can have an effect on how light travels within the diamond, and how it exits in the form of brilliance.

Too Shallow: Light is lost out the bottom causing the diamond to lose brilliance.

Too Deep: Light escapes out the sides causing the diamond to appear dark and dull.

Determining a diamond's cut grade, however, goes beyond simple measurements of width and depth. Using an optical measuring device, a three-dimensional model is created to determine the diamond's proportions and angles. The interrelations between these various dimensions will greatly affect how light reacts once it enters and how it behaves once it exits; by using sophisticated computer modeling, it is possible to trace light behavior and measure its levels of brightness, fire and scintillation - the face-up appearance.

Brightness: The reflections of white light seen when a diamond is viewed from the top.

Fire: The flashes of coloured light reflected back from within a diamond, comparable to a prism. In general, higher grade diamond cuts refract more colours when turned in the light.

Scintillation: A general term referring to the flashes of light seen when a diamond moves. Also used to describe the patterns of light and dark areas seen in a diamond.

Diamond Anatomy

Diameter: The width of the diamond as measured through the girdle.

Table: The largest facet of a gemstone.

Crown: The top portion of a diamond extending from the girdle to the table.

Girdle: The intersection of the crown and pavilion which defines the perimeter of the diamond.

Pavilion: The bottom portion of a diamond, extending from the girdle to the culet.

Culet: The facet at the tip of a gemstone. The preferred culet is not visible with the unaided eye (graded "none" or "small").

Depth: The height of a gemstone measured from the culet to the table

Polish and Symmetry affect sparkle

Polish and symmetry are two important aspects of the cutting process. The polish grade describes the smoothness of the diamond's facets, and the symmetry grade refers to alignment of the facets. With poor polish, the surface of a facet can be dulled, and may create blurred or dulled sparkle. With poor symmetry, light can be misdirected as it enters and exits the diamond. The polish and symmetry grades are clearly listed in each diamond detail page and within the GIA or AGSL diamond grading report. For the most beautiful diamond, look for a symmetry grade of excellent (EX), very good (VG), or good (G) for a GIA graded diamond, and ideal (ID), excellent (EX), very good (VG), or good (G) for an AGSL graded diamond. Avoid diamonds with symmetry grades of fair (F) or poor (P), as the alignment of their facets may misdirect light so severely that it affects the brilliance of the diamond.

Diamond measurements are calculated and applied to a cut grading scale that makes it easy to understand how well each reflect light:

Nirvana Diamonds Premier Cru Ideal cut: Represents roughly the top 1% of diamond quality based on cut. The highest grades of polish and symmetry allow it to reflect even more light than the standard ideal cut. Our most brilliant cut.

Ideal cut: Represents roughly the top 3% of diamond quality based on cut. Reflects nearly all light that enters the diamond. An exquisite and rare cut.  

Very good cut: Represents roughly the top 15% of diamond quality based on cut. Reflects nearly as much light as the ideal cut, but for a lower price.  

Good cut: Represents roughly the top 25% of diamond quality based on cut. Reflects most light that enters. Much less expensive than a very good cut.  

Fair cut: Represents roughly the top 35% of diamond quality based on cut. Still a quality diamond, but a fair cut will not be as brilliant as a good cut.  

Poor cut: This includes all diamonds that do not meet the performance standards of a fair cut. These diamonds are generally deep and narrow or shallow and wide and tend to lose most of the light out the sides and bottom. Nirvana Diamonds does not carry diamonds with cut grades of poor.  

Nirvana Diamonds do not carry diamonds with cut grades lower than fair, which are generally either too shallow or too deep to present an acceptable level of brilliance.

Which cut grade is best?

For a diamond with the best cut, that will look exceptional even when viewed under a microscope look for ideal or very good cut. These diamonds reflect the most brilliance because they are cut to the most exacting proportions. They have the highest polish and symmetry grades available.

For the best value in a brilliant diamond, choose a diamond with a cut grade of good or very good, and polish and symmetry grades of very good or good.

If your diamond has an ideal or very good cut with very good or good polish and symmetry, you may want to consider less expensive grades of colour and clarity — look for a diamond with G or H colour and SI1 or SI2 clarity.

Colour

Acting as a prism, a diamond can divide light into a spectrum of colours and reflect this light as colourful flashes called fire. Just as when looking through coloured glass, colour in a diamond will act as a filter, and will diminish the spectrum of colour emitted. The less colour in a diamond, the more colourful the fire, and the better the colour grade.

D: Absolutely colourless. The highest colour grade, which is extremely rare.

E: Colourless. Only minute traces of colour can be detected by an expert gemologist. A rare diamond.

F: Colourless. Slight colour detected by an expert gemologist, but still considered a "colourless" grade. A high-quality diamond.

G-H: Near-colourless. Colour noticeable when compared to diamonds of better grades, but these grades offer excellent value.

I-J: Near-colourless. Colour slightly detectable. An excellent value.

K-M: Not carried at Nirvana Diamonds.

N-Z: Not carried at Nirvana Diamonds.

At Nirvana Diamonds, you'll find only the finest diamonds with colour graded D-J. Diamonds graded better than J are colourless or near-colourless — their colour is typically undetectable to the unaided eye.

A note about fluorescence

Some people seek diamonds that produce this unique effect, while others definitely avoid it. The visible effects of fluorescence grades of faint, inert, negligible, and medium, can only be detected by a trained gemologist. A fluorescence grade of strong or very strong can make a diamond with a near-colourless grade look even whiter yet in some instances give the diamond a slight hazy or oily appearance. Diamonds with a strong or very strong fluorescence are priced slightly lower than other diamonds.

Fluorescence: A reaction to UV light. Fluorescence is graded from None to Very Strong. A fluorescence grade of Very Strong can make a diamond with a near-colourless grade look even whiter and could, in some instances, give the diamond a slight hazy or oily appearance. Diamonds with a strong or very strong fluorescence are priced slightly lower than other diamonds.

What colour grade is best?

For the purist, look for a colourless diamond with a grade of D-F and a fluorescence rating of faint, inert, none, or negligible.

For an excellent value in a diamond with no noticeable colour to the unaided eye, look for a near-colourless grade of G-I, and a fluorescence grade of medium or strong blue.

Or, if you'd rather not compromise on colour but would like to stay on budget, choose a diamond with a good cut, SI1–SI2 clarity, and consider going with a strong fluorescence. It will still be beautiful to the unaided eye and you may prefer the unique effect of a strong fluorescence.

Clarity

Diamonds that are absolutely clear are the most sought-after, most rare and therefore the most expensive. But many diamonds have inclusions — scratches, trace minerals or other tiny characteristics that can detract from the pure beauty of the diamond. The GIA and AGSL use a detailed system of rules and standards to summarize the number, location, size, and type of inclusions present in a diamond.

IF Diamonds: Flawless: No internal or external flaws. Internally Flawless: No internal flaws. Very rare and beautiful diamonds.

VVS1, VVS2 Diamonds: Very, Very Slightly Included: Very difficult to see inclusions under 10x magnification. An excellent quality diamond. Requires 60x magnification to see inclusions.

VS1, VS2 Diamonds: Very Slightly Included: Inclusions are not typically visible to the unaided eye. Less expensive than the VVS1 or VVS2 grades. Requires 30x magnification to see inclusions.

SI1, SI2 Diamonds: Slightly Included: Inclusions are visible under 10x magnification, and may be visible with the unaided eye. A good diamond value.

I1, I2, I3 Diamonds: Included: Nirvana Diamonds does not carry diamonds of I-grade clarity.

What clarity grade is best?

The clearer the diamond, the greater its brilliance and the greater its value. Most diamonds have blemishes, called 'inclusions' which are nature's birthmark of the stone. These can be tiny traces of carbon (black spots), air pockets (white spots) or other naturally occurring phenomena. Diamond clarity ranges from diamonds without any flaws (internally flawless) to those that have visible inclusions. At Nirvana Diamonds, our minimum quality threshold is SI2 ("small inclusions" - not visible with the naked eye). For comparison purposes, the majority of diamonds in a high street jewellers are 'Commercial grade' quality which, if graded on this scale, would be approx clarity I1 / I2.

Carat Weight

When diamonds are mined, large gems are discovered much less frequently than small ones, which makes large diamonds much more valuable. In fact, diamond prices rise exponentially with carat weight. So, a 2-carat diamond of a given quality is always worth more than two 1-carat diamonds of the same quality.

What size is best?

To choose the best carat weight of diamond, consider her style, the size of her finger, the size of your setting, and your budget.

• If you have a set budget, explore all your options and you'll find that there is a wide range of diamond carat weights and qualities available in your price range.
• If your recipient is very active or not used to wearing jewellery, she may find herself bumping or nicking her new ring. Consider a smaller size diamond or a setting that protects a larger diamond from getting knocked against doors and counters.
• Also keep in mind that the smaller the finger, the larger the diamond will appear. A 1½-carat diamond solitaire looks much larger on a size 4 finger than a size 8.
• If you have already chosen a setting, make sure you choose a diamond to fit. Look for the diamond size specifications of your ring or ask us what size diamond you should look for.
• Finally, if a large carat weight is important to you, yet you're working within a budget, consider a diamond with a good cut, SI1–SI2 clarity, and an I or J colour grade.
  

But the best way to determine what size is best is by getting an idea of what she is expecting. If you plan carefully, you can get some answers without even raising her suspicions.