Precious Gemstones
Where a diamond consists of only one element, a gemstone is a compound – it consists of two or more elements.
Gemstones are naturally formed crystals produced from compounds/elements. They can vary in composition, color, hardness, and origin, including minerals like rubies, sapphires, emeralds, and various semi-precious stones.
A diamond is a specific type of gemstone that is known for its exceptional hardness and brilliance, however only represent a distinct subset within the larger realm of gemstones. The main difference between a diamond and other gems, is that a diamond is formed from a single element, being high pressured carbon.
Gemstones are graded differently than diamonds. While diamonds have their own standardized grading system known as the 4Cs (Carat weight, Color, Clarity, and Cut), other gemstones are evaluated based on their individual characteristics.
In order to maintain a uniform system of judging and grading stones, GIA made a Colored Stone Grading Scheme.
Gemstones are graded based on Clarity, Carat, Cut, and Color being by far the most important factor.
Color
If the color is exceptional, the clarity and cut are not as important.Many times you will see that colored stones are cut in what we call native cuts. In native cuts, the gem cutter has spent a lot of time getting the best color out of the stone.Let me explain a bit:Color is judged in 3 different ways:
- Hue is the first impression of a stone’s color, which is the body color of the stone. Hue tells the color of the stone, and whether it has a trace of another color.
- Normally, we prefer stones with a pure color. However, it depends on the stone.
- Tone is the darkness or lightness of the color, which is graded from very light to very dark. The most valuable stones will be medium light, medium, and medium dark.
- Saturation is the color’s strength or intensity. It determines how much color the stone holds. The finest saturations will be judged as moderately strong, strong or vivid, with the latter being most valuable.
Normally, the most valuable stone will be the one with the purest body color and the strongest saturation. This means that it’s full of color without getting dark.
Clarity
Gemstone clarity refers to the presence or absence of internal flaws (inclusions) and surface irregularities (blemishes).
Unlike diamonds, which have a strict clarity scale, gemstone clarity grading is more subjective and can vary depending on the type of gem. Some gemstones are expected to have visible inclusions, while others are prized for their transparency and lack of flaws.
Cut
A colored gemstone is cut differently from a diamond.
When cutting colored stones, the gem cutter tries to retain as much weight as possible, but the main focus is on how to get the optimal color out of each gemstone.
This is why you will find colored stones in all different cuts and shapes.
Carat
Carat weight is a universal measurement for gemstones, including diamonds.
It represents the weight of the gemstone and is used to determine its size. Gemstones are typically measured in carats, with one carat equal to 0.2 grams.
