Clarity
The below clarity grading scheme is in accordance with the GIA (Gemological Institute of America). It is important to note that the GIA Grading system is not static, and has changed slowly over time.
Be aware! Two methods used to enhance the clarity grade given to a diamond are laser drilling and fracture filling. Laser drilling is the process in which a laser is used to drill a tiny hole into a diamond and the black of the imperfection is then removed. The second treatment is fracture filling. This method is not permanent and therefore not recommended. All clarity treated diamonds must be disclosed as such prior to sale.
| Symbol | Meaning | Definition |
|---|---|---|
| F | Flawless | Free from all inclusions or blemishes. |
| IF | Internally Flawless | No inclusions visible at 10x magnification. |
| VVS1 | Very Very Slightly Included #1 | Inclusions that are extremely difficult to locate at 10x. |
| VVS2 | Very Very Slightly Included #1 | Inclusions that are extremely difficult to locate at 10x. |
| VS1 | Very Slightly Included #1 | Minor inclusions that are somewhat difficult to locate at 10x. |
| VS2 | Very Slightly Included #2 | Minor inclusions that are somewhat difficult to locate at 10x. |
| SI1 | Slightly Included #1 | Noticeable inclusions that are easy to locate at 10x. |
| Sl2 | Slightly Included #2 | Noticeable inclusion that are very easy to locate at 10x. |
| I1 | Included #1 | Obvious inclusions. Somewhat easy to locate with the unaided eye. |
| I2 | Included #2 | Obvious inclusions. Easy to locate with the unaided eye. |
| I3 | Included #3 | Obvious inclusions. Very easy to locate with the unaided eye. |
Colour
Colour describes the amount of colour the diamond contains. This can range from colourless to yellow with slight tints of yellow, gray or brown. Colours can also range from intense yellow to brown, blue, green, pink and red. These fancy colours are rare and therefore more valuable.
| GIA | Colour - Commercial Grading |
|---|---|
| D, E, F, G, H, I | Colourless (White) |
| J, K, L | Near Colourless (White) |
| M | Faint Yellow |
| N, O, P, Q, R | Very Light Yellow |
| S, T, U, V, W, X, Y, Z | Light Yellow |
Be aware! It is possible to influence the colour by irradiation treatment followed by heat treatment. This method is not recommended for two reasons. The first is the risk involved with exposure to irradiated objects. The second is the risk of colour change over time. All colour treated diamonds must be disclosed as such prior to sale.
The colour of the stone can be determined by using a GIA (Gemological Institute of America) Certified set of master stones and/or the Colorimeter, a computer which accurately grades the colour of a polished diamond.
For example, for a round brilliant cut diamond, table percentage is calculated as follows:
Table (%) = longest table measurement (mm) / average girdle diameter (MM)
And for depth percentage:
Depth (%) = depth (mm) / average girdle diameter (mm)
Without attention to quality cutting, light is lost and not returned to the eye.
| Premium | Tolkowsky Ideal | Excellent Ideal | |
|---|---|---|---|
| Total Depth | 58.8% - 63.8% | 58.0% - 63.8% | 59.2% - 62.4% |
| Table Size | 58.0% - 61.0% | 53.0% - 58.0% | 52.5% - 58.4% |
| Crown Height | 13.0% - 17.0% | 14.2% - 16.2% | -------------- |
| Crown Angle | 32.7° - 36.3° | 33.7° - 35.8° | 32.5° - 35.4° |
| Pavilion Depth | 41.7% - 45.0% | 42.2% - 43.8% | 41.5% - 44.4% |
Cut
This is the one factor not predetermined by nature.
The "cut" grade of a diamond refers to the preciseness of the diamonds angles, the symmetry of the cut and the surface polish, which make up the overall reflective qualities of the stone.
The beauty depends upon three factors: Brilliance, Dispersion (fire) and Scintillation (sparkle).
Diamond cutting is based on specific optical calculations aimed at maximizing its beauty.
Diameter
The width of the diamond as measured through the girdle.
Table
This is the large, flat top facet of a diamond.
Crown
The upper portion of a cut gemstone, above the girdle.
Girdle
The narrow rim of a diamond that separates the crown from the pavilion. It is the largest diameter to any part of the stone.
Pavilion
The lower portion of the diamond, below the girdle. It is sometimes referred to as the base.
Culet
The tiny facet on the pointed bottom of the pavilion, which is the portion of a cut gem below the girdle.
Depth
The height of a gemstone, from the culet to the table.
In a poorly cut diamond, the light that enters through the table reaches the facets and then 'leaks' out from the sides or bottom of the diamond rather than reflecting back to the eye. Less light reflected back to the eye means less brilliance.
The best cut diamonds are those that follow a formula calculated to maximize brilliance. The most important factor is how the depth compares to the diameter, and how the diameter of the table compares to the diameter of the diamond.
Carat
Carat is the unit of weight for the diamond. A carat is further subdivided in 100 points ( 0.01 carat = l point ). One carat is equal to 0.20 grams. Value per carat increases with carat size, because larger rough diamonds occur less frequently. In other words, 2 half-carat diamonds taken together will not cost as much as 1 one-carat diamond, as the one-carat stone is more rare.
Jewellery Cleaning
Diamonds and jewellery are susceptible to becoming dirty, oily and dusty with make-up, powders, soaps and the oils from skin, which combine to obscure the brilliance and shine of your jewellery.
Custom made rings are stronger than cast rings, but still lose their shine, so the best way to take care of your jewellery is to let DDS Diamonds Adelaide and Moser Jewellery take care of it for you. We will polish using a high speed buff, followed by immersing the jewellery in an high frequency ultrasonic cleaner, with a mixture of water, ammonia and detergent that removes the dirt and polishing compound from hard to get at places in your setting.
All manufacturing jewellers in Adelaide should have the proper cleaning equipment, but DDS Diamonds in Burnside will make your rings look new again.
Home Cleaning
Please follow these procedures if you wish to clean your jewellery at home.
1. Place your jewellery in a solution of 5% dish washing detergent and 90% boiled water for 20-30 minutes.
2. Use a toothbrush with the same solution to scrub up and under the settings.
3. Finally rinse the jewellery under a warm tap and dry with tissues.
This process should not be used for emeralds, pearls, opals or any other soft or porous stone.
