Education
Diamond Cut:
It takes a painstaking amount of work, to make diamonds as beautiful as you’ll see in their polished life, as they start out as an uneven natural state called a ‘rough.’ Every other aspect of the diamond is an act of nature; however, the cut is the only part of diamond creation that requires a human input. It’s the most important, yet the most misunderstood part of the process. Diamond cutting is an art and it can take weeks to produce the perfect outcome.
Cutting is so important because it unlocks a diamond’s beauty and sparkle. A perfectly cut diamond will be so eye-catching thanks to its brightness, fire and scintillation.
Brilliance, Polish and Symmetry of a Diamond
The Cut of a diamond produces its Brilliance (reflection of light), whereas Polish (smoothness of facets) and Symmetry (alignment of facets) affect the sparkle of a diamond. A poor polish can make a diamond look dull and a poor symmetry can misdirect the light reducing the sparkle or creating a strange appearance in the stone.
Types of Cut:
There are three types of cuts as shown in the figure:
Shallow Cut:
If a diamond is cut too shallow, the light will disappear through the bottom of the stone.
Ideal Cut
If a diamond has an ideal cut it means the angles are perfect for the performance of light and the light will come back through the top of the diamond
Deep Cut
If a diamond is a deep cut. The light will not make it back to the top of the stone it will be lost out the side and will look flat and lifeless.
GIA Cut Grading
Diamond cuts are graded on the following scale established by the Gemmological Institute of America (GIA):
- Excellent Cut: The rarest cut grade of all, Excellent cut stones reflect the maximum light entering the diamond and they will shine with optimum brilliance.
- Very Good Cut: Very Good cut grade is close to perfect, but some small angles may be slightly off, affecting the light performance marginally.
- Good Cut: Good cut grade of a diamond helps reflect light to obtain a good amount of brilliance, though not equal to the Excellent or Very Good cut.
- Fair Cut: Being not as brilliant as a Good cut, Fair cut grade quality diamonds refract less amount of light but make a better choice than Poor cut diamonds.
Diamond Dimensions
The various dimensions of a diamond are defined as follows:
- Table: The topmost and largest facet of a diamond.
- Crown: The sloping section of a diamond- from the girdle to the table.
- Girdle: The point where the crown and pavilion meet, which also determines the perimeter of the diamond.
- Diameter: The width of the diamond measured with reference to the girdle.
- Pavilion: The lower section of a diamond from the girdle to the culet.
- Culet: The tip of a diamond (the best culet is invisible to the naked eye).
- Depth: The height of a diamond measured from the culet to the table.
Starfire Diamond Jewellery Ideal Cut Grade
At Starfire we pride ourselves in providing extremely high-quality diamonds. We stock no less than Ex-VG cut stones and see the cut as one of the leading factors that should be considered when purchasing a stone.
Diamond Clarity
Clarity refers to the number, location, size and type of ‘inclusions’ within a diamond. These are tiny little marks present inside the diamond. Like nature’s birthmarks, they are also known as clarity characteristics and are completely natural in diamond formation.
A truly flawless diamond is extremely rare as it’s possible to find these little specks and birthmarks in almost every diamond in the world. The fewer or smaller the clarity characteristics creates a rarer and more valuable diamond.
GIA Clarity Grading
The Gemmological Institute of America (GIA) has various grading scales to judge the purity of a diamond. They are:
- FL(Flawless) - Diamonds that are absolutely flawless i.e., no inclusions or blemishes are seen to a skilled grader using 10x magnification.
- IF (Internally Flawless) -Diamonds those have no inclusions, but slight blemishes appear externally to a skilled grader using 10x magnification.
- VVS1, VVS2(Very, Very Slightly Included) - Most sought after diamonds with very-very small inclusions internally even difficult for a skilled grader to identify under 10x magnification.
- S1, VS2(Very Slightly Included) - Diamonds with very slight inclusions clearly visible to a skilled grader using 10x magnification.
- SI1, SI2(Slightly Included) - Diamonds with slight inclusions noticeable to a skilled grader using 10x magnification.
- I1, I2 and I3(Included) - Diamonds with inclusions obviously visible under 10x magnification, can often be seen with the naked eye..
Starfire Diamond Jewellery Ideal Clarity Grade:
If you prefer a diamond with no inclusions visible to the naked eye, then VS1 or VS2 would be an ideal clarity match for you. However, diamonds with SI1 or SI2 clarity are also a popular choice and are generally referred to as Eye-Clean Diamonds.
What is the definition of Eye-Clean?
No inclusions visible to the naked eye from the top of the diamond. Usually eye clean stones will be in the FL-SI range of clarity
Diamond Colour
Diamonds come in a vast range of natural colours and each is unique and mesmerising. To grade diamond colour, there is a scale to follow to find the Whitest diamonds in the world.
The diamond colour alphabet begins at ‘D’ and runs to ‘Z’ from completely colourless to diamonds with a warm yellow tone. The human eye is naturally more attracted to whiter diamonds; these are more rare and valuable.
Types of Colours
Most diamonds sold in the retail trade run from near colourless to slightly yellow or brown. Diamonds are also found in a variety of other colours such as black, grey, blue, green, yellow, brown, orange, pink and the rarest of all, red. Diamonds with distinct tints other than the normal colours are classified as Fancy colours.
Fluorescence of a Diamond
Fluorescence is the property which is seen in some diamonds when they are exposed to ultraviolet light. It causes diamonds to usually shine blue but can present itself as yellow or other colours also. It is not an ideal quality in a diamond however if it is faint it can make the apparent colour of the diamond slightly brighter.
GIA Colour Grading
Diamonds are graded on a colour scale established by the Gemmological Institute of America (GIA) which ranges from D (colourless) to Z. The GIA grades diamonds in the following colour scale:
- D, E, F: Colourless
- G, H, I, J: Near Colourless
- K, L, M: Faint Yellow or Faint Brown
- N, O, P, Q, R: Very Light Yellow or Very Light Brown
- S to Z: Light Yellow or Light Brown
Starfire Diamond Jewellery Ideal Colour Grade
D-H colour grades with faint or no fluorescence are a perfect choice. We stock the highest quality stones available and pride ourselves in our high standards.
Diamond carat/karat:
Carat is probably the most talked about aspect of a diamond. It refers to its weight and its overall size. Usually, the bigger the diamond, the higher the carat number. However, when comparing two diamonds, a smaller diamond may be more valuable than a larger diamond if it possesses a far superior cut, whiter colour and higher clarity grade.
Remember, the cut of a diamond is above all the most important, so bear that in mind when shopping for the perfect diamond. You want the cut to be absolutely perfect or the carat becomes just another number.
Measurement of a Diamond
Like many other gemstones, diamonds are also weighed in metric carats where 1 carat = 0.2 grams. Fraction of a carat can make a huge value difference, even in the case of smaller diamonds. That is why diamonds are weighed in a thousandth of a carat and rounded to the nearest hundredth point. Diamond range starts from a small point to more than 100 carat, but in regular diamond market people shop for diamonds ranging from 5 points to 3 carat.
While purchasing diamonds, people generally consider the total carat weight of all diamonds present in a jewellery piece and do not talk about the individual weight of each diamond. E.g. if a ring carries fifty 1 point diamonds or two quarter carat diamonds or a single half carat diamond, the total diamond weight is observed as half carat in all cases, however the prices may vary considerably, being the highest for a single half carat diamond.
Cullinan is the largest rough gem diamond ever discovered and it weighs around 3,106.75 carats, while Golden Jubilee Diamond weighing 545.67 carats is the largest polished diamond.
Diamond Relative Carat / Size Comparison
Carat is a measurement of weight, not size and so the overall diameter (mm) could differ slightly even though the carat weight is correct. Image is not to scale. Diamond pictures are shown for comparison purpose only. Actual size
can vary depending on your screen resolution, monitor size, etc. Loose diamonds can be weighed on a jeweller’s balance. However, if the diamond is mounted, the weight is estimated using the weight-estimation formula. Estimating weight in this fashion is less precise but enough to let appraisers make reasonable evaluations without demounting the diamonds.
Diamond Shape
Diamonds are natural crystals that can be cut into a large variety of shapes such as round, princess, heart, oval, marquise etc. The following information will help you to choose the right shaped diamond.
Brilliant Round
A classic diamond to most people is a round gem of sparkling white brilliance with a kaleidoscope of dazzling facets. This shape has set the standard for all other diamond shapes and accounts for more than 75% of diamonds sold today.
Princess Cut
Princess is a brilliant square diamond with sharp, uncut corners and pavilion facets that are wide at the culet and narrowed towards the girdle. Princess is one of the most popular cuts in the world after the brilliant round.
Oval Cut
It is similar to the round diamond in sparkle and brilliance. A perfectly symmetrical oval diamond is very popular as a centre diamond piece for engagement rings and among women with small hands or short fingers as they make fingers appear long and slender.
Marquise Cut
Marquise is a boat-shaped modified round diamond with pointed ends. Its elongated shape makes fingers look long and slender. It is very essential to choose a diamond with perfect facet alignment to retain its brilliance.
Pear Cut
Pear shaped diamond is shaped almost like a sparkling tear drop. It compliments hands with small or average length fingers. Elongated pear diamonds are preferably used in earrings and necklaces, while smaller pear-shaped diamonds are used in rings.
Heart Cut
This ultimate symbol of romance essentially shaped like a heart, is an ultimate gift for Valentine’s Day. A very flat diamond appears big, but lacks brilliance, while an overly deep diamond’s brilliance looks good but the diamond looks smaller than the ideal.
Emerald Cut
Emerald diamond is a step-cut diamond having a row of elongated facets (usually 48 to 50) that resembles a stair case. The flat planes of the outside edges allow for a variety of side stone shapes.
Radiant Cut
This square or rectangular shape diamond has 70 facets that maximize the effect of its colour refraction. Similar in outside shape to an emerald but with Kite shaped facets.
Cushion Cut
A cushion cut is square or rectangular in shape with rounded corners and 58 brilliant facets that resemble a pillow shape, hence the name.
Ascher Cut
The Asscher cut is a variation of the Emerald cut except that it is square. It is characterized by a small table and large steps.
Diamond Certificate
All of our diamonds come along with a Diamond Certificate from an independent laboratory. This showcases the characteristics of the diamond like its Cut, Colour, Clarity and Carat weight which gives you extra piece of mind to know what you are purchasing. It acts like a passport which tells you all about your diamond’s credentials and ensures your stone has come from a repeatable source.
A Diamond Certificate certainly can’t explain why you may love one diamond more than another however it gives peace of mind that you have all the information available about your stone.
The Gemmological Institute of America (GIA) is the world’s largest and most respected non-profit institute of gemmological research and learning. The GIA Gem Trade Laboratory was established in 1949 and has grown to nearly 400 staff operating in New York and California. The GIA Diamond Grading Report includes a full page A4 report, or an A5 Diamond Dossier, with a diagram of your diamond’s clarity characteristics and unique security features.
Which Gemmological Labs are reliable?
The Gemmological Institute of America (GIA):
GIA is the most reputed and reliable laboratory for gem evaluation as it has developed the first internationally accepted Diamond Grading System and set the standard for diamond quality documentation around the world. The GIA Gem Trade Laboratory issues these reports on a majority of high quality diamonds over one carat in size.
How to Read a GIA Diamond Grading sample Report
The GIA Diamond Grading Report includes an assessment of the 4Cs – Colour, Clarity, Cut, and Carat Weight – along with a plotted diagram of its clarity characteristics and a graphic representation of the diamond’s proportions. GIA issues the Diamond Grading Report for loose natural diamonds only, weighing 0.15 carats or more. For standard round brilliant cut diamonds falling in the D-to-Z color range, the report also includes a GIA Cut grade.
DATE
Date diamond was examined by GIA.
REPORT NUMBER
Unique GIA report number registered in GIA’s extensive global database.
SHAPE AND CUTTING STYLE
The outline of the diamond (shape) and the pattern of the facet arrangement (cutting style).
MEASUREMENTS
Diamond dimensions listed as “minimum diameter – maximum diameter x depth” for round diamonds and “length x width x depth” for fancy-shaped diamonds.
CARAT WEIGHT
Weight given in carats, recorded to the nearest hundredth of a carat. One carat is equal to 1/5 of a gram.
COLOR GRADE
The absence of colour ranging from colourless to light yellow or brown when compared to GIA Master Colour Comparison Diamonds. Graded on a D-to-Z scale. If “*” appears next to the colour grade, a colour treatment was detected.
CLARITY GRADE
The relative absence of inclusions and blemishes. Graded on a scale from Flawless to Included based on size, nature, number, position, and relief of characteristics visible under 10x magnification.
CUT GRADE
For standard, D-to-Z colour, round brilliant diamonds. Cut grade incorporates the aspects of face-up appearance, design, and craftsmanship. Graded on a scale from Excellent to Poor.
POLISH
Smoothness of the diamond’s surface assessed on a scale ranging from Excellent to Poor.
SYMMETRY
Exactness of the diamond’s outline, and the shape, placement, and alignment of its facets, assessed on a scale ranging from Excellent to Poor.
FLUORESCENCE
Strength and colour of the diamond when viewed under long-wave ultraviolet light. A fluorescence description of “none” represents a range of fluorescence from Indiscernible to Very Faint. Used for identification purposes.
INSCRIPTION(S)
Any text, symbols, logos, or a unique GIA report number inscribed on the diamond’s girdle.
COMMENTS
Additional identifying characteristics or features that are not otherwise represented on the report. If a treatment is detected, such as laser drilling, it would be described here.
PROPORTION DIAGRAM
Graphic profile representation of the diamond’s actual proportions.
PLOTTED DIAGRAM
Approximates the shape and cutting style of the diamond. Symbols indicate the type or nature, position, and the approximate size of a clarity characteristic.
KEY TO SYMBOLS
Lists the characteristics and symbols shown on the plotting diagram, if present.
GIA COLOR SCALE
Illustrates the GIA Colour grades and their relative positions in the GIA Diamond Colour Grading System.
GIA CLARITY SCALE
Illustrates the GIA Clarity grades and their relative positions in the GIA Diamond Clarity Grading System.
GIA CUT SCALE
Illustrates the GIA Cut grades and their relative position in the GIA Diamond Cut Grading System. Available for standard round brilliant cut diamonds in the D-to-Z color range and Flawless-to-I3 clarity range.
SECURITY FEATURES
Microprinting, security screens, watermarks, a two-dimensional barcode, a hologram, and sheet numbering safeguard report integrity and facilitate document authentication.
QR CODE
A two-dimensional barcode that, when scanned, verifies data on the report against the GIA database.
