Basic Gemstone Details:
Unlike diamonds, there is no official 'world grading' of colored gemstones. Despite this, you can use many of the same principles as with diamonds. Before you buy a gemstone, it is important that you have a general idea of the 4 C's of gemstones. C is in reference to the English words for Color, Cut, Carat Weight and Clarity.
Color:
Color is probably the most important factor to consider when buying a gemstone. The color of a stone should preferably be vibrant, even and not too dark. In general, you can say that the value of a stone increases with how beautiful it looks.
Many stones also have a mix of different color shades, which usually makes them even more attractive and valuable. Examples of these types of stones are Tanzanites which have a purple-blue color, or Sphene which has a green-rainbow color.
In some gemstones you can see unusual optical effects. These effects usually increase the value of the individual stone. Examples of these types of effects are stars (often found in Sapphires and Rubies), cat's eye (often found in Tourmaline, Chrysoberyl) and color change (often found in Alexandrites, Sapphires, Garnets).
Gem Cut:
Cutting a gemstone does not affect the value as much as with diamonds. Despite this, it is important that a gemstone has a good cut so that maximum beauty can be found out of the individual stone. When cutting a gemstone, you want minimal inclusions, good luster and even color distribution. It is also important not to have a cut stone that is too deep because then you lose a lot of the weight in the bottom of the stone, instead of in the face (the part of the stone you see from above). You also don't want a too thin cut stone where most of the weight is on the front. You then get an effect called a window where much of the luster disappears.
One can divide the cutting of precious stones into two categories, Faceted and Non-Faceted. The most common cuts are,
Oval
Round
Emerald
Heart
Pear
Marquise
Princess
Square
Baguette
Trilliant
Cushion
Carat Weight:
Like diamonds, the weight of precious stones is measured in carats. The word carat comes from the traditional use of carob seeds to weigh gemstones. Carob seeds were used because they always had the same weight and shape. 1 carat equals 0.2 grams, so 5 carats equals 1 gram. The carat is also divided into so-called points, where 100 points are equal to 1 carat. Points are used more in the diamond industry, but you also come across them when dealing with colored gemstones.
The prices of precious stones increase exponentially as the weight increases. For example, a 5 carat Sapphire is always worth much more than 5 pieces of 1 carat Sapphires of the same quality.
Clarity:
In some gemstones you can see small impurities called inclusions. The clarity of a gemstone is graded by seeing how much/little inclusions the stone has. The less inclusions a stone has, the more valuable it is.
However, there are certain types of gemstones where inclusions are accepted and actually sought after. Types such as rubies and emeralds should preferably have inclusions in them to increase the value of the stone.
Below are the clarity definitions Gemsheaven uses.
Clarity Scale:
IF (Internally Flawless) - These stones are free of inclusions under 10x magnification.
VVS1-VVS2 (Very, Very Slightly Included) - Extremely few inclusions can possibly be seen under 10x magnification.
VS1-VS2 (Very Slightly Included) - Very few inclusions that can be seen under 10x magnification.
SI1-SI3 (Slightly Included) - Few inclusions that can be seen under 10x magnification.
I1-I2 (Included) - These stones have inclusions that are easily seen under 10x magnification.
PK (Pique) - These stones have inclusions that can be easily seen with the naked eye.
Treatment:
Treatment of precious stones is nowadays more common than unusual. More than 99% of all gemstones are treated, usually with heat. Treatment is done to improve the quality of a stone. For example, Tanzanite which is one of the world's most sought after gemstones actually has a rather ugly brownish color when found in the ground. It is only after a light heat treatment that it gets its incredibly beautiful blue/purple color.
The most common type of treatment is heat, but many stones are also treated with "irradiation". Despite the name, this is a completely harmless treatment that is permanent. Although treatment is very common, there are stones that are not treated such as tourmalines, garnet stones, fluorite, alexandrite, white diamonds and more. If you would like information about a particular stone or stone variety, please contact us or refer to our info pages for each individual gem type.
Unlike diamonds, there is no official 'world grading' of colored gemstones. Despite this, you can use many of the same principles as with diamonds. Before you buy a gemstone, it is important that you have a general idea of the 4 C's of gemstones. C is in reference to the English words for Color, Cut, Carat Weight and Clarity.
Color:
Color is probably the most important factor to consider when buying a gemstone. The color of a stone should preferably be vibrant, even and not too dark. In general, you can say that the value of a stone increases with how beautiful it looks.
Many stones also have a mix of different color shades, which usually makes them even more attractive and valuable. Examples of these types of stones are Tanzanites which have a purple-blue color, or Sphene which has a green-rainbow color.
In some gemstones you can see unusual optical effects. These effects usually increase the value of the individual stone. Examples of these types of effects are stars (often found in Sapphires and Rubies), cat's eye (often found in Tourmaline, Chrysoberyl) and color change (often found in Alexandrites, Sapphires, Garnets).
Gem Cut:
Cutting a gemstone does not affect the value as much as with diamonds. Despite this, it is important that a gemstone has a good cut so that maximum beauty can be found out of the individual stone. When cutting a gemstone, you want minimal inclusions, good luster and even color distribution. It is also important not to have a cut stone that is too deep because then you lose a lot of the weight in the bottom of the stone, instead of in the face (the part of the stone you see from above). You also don't want a too thin cut stone where most of the weight is on the front. You then get an effect called a window where much of the luster disappears.
One can divide the cutting of precious stones into two categories, Faceted and Non-Faceted. The most common cuts are,
Oval
Round
Emerald
Heart
Pear
Marquise
Princess
Square
Baguette
Trilliant
Cushion
Carat Weight:
Like diamonds, the weight of precious stones is measured in carats. The word carat comes from the traditional use of carob seeds to weigh gemstones. Carob seeds were used because they always had the same weight and shape. 1 carat equals 0.2 grams, so 5 carats equals 1 gram. The carat is also divided into so-called points, where 100 points are equal to 1 carat. Points are used more in the diamond industry, but you also come across them when dealing with colored gemstones.
The prices of precious stones increase exponentially as the weight increases. For example, a 5 carat Sapphire is always worth much more than 5 pieces of 1 carat Sapphires of the same quality.
Clarity:
In some gemstones you can see small impurities called inclusions. The clarity of a gemstone is graded by seeing how much/little inclusions the stone has. The less inclusions a stone has, the more valuable it is.
However, there are certain types of gemstones where inclusions are accepted and actually sought after. Types such as rubies and emeralds should preferably have inclusions in them to increase the value of the stone.
Below are the clarity definitions Gemsheaven uses.
Clarity Scale:
IF (Internally Flawless) - These stones are free of inclusions under 10x magnification.
VVS1-VVS2 (Very, Very Slightly Included) - Extremely few inclusions can possibly be seen under 10x magnification.
VS1-VS2 (Very Slightly Included) - Very few inclusions that can be seen under 10x magnification.
SI1-SI3 (Slightly Included) - Few inclusions that can be seen under 10x magnification.
I1-I2 (Included) - These stones have inclusions that are easily seen under 10x magnification.
PK (Pique) - These stones have inclusions that can be easily seen with the naked eye.
Treatment:
Treatment of precious stones is nowadays more common than unusual. More than 99% of all gemstones are treated, usually with heat. Treatment is done to improve the quality of a stone. For example, Tanzanite which is one of the world's most sought after gemstones actually has a rather ugly brownish color when found in the ground. It is only after a light heat treatment that it gets its incredibly beautiful blue/purple color.
The most common type of treatment is heat, but many stones are also treated with "irradiation". Despite the name, this is a completely harmless treatment that is permanent. Although treatment is very common, there are stones that are not treated such as tourmalines, garnet stones, fluorite, alexandrite, white diamonds and more. If you would like information about a particular stone or stone variety, please contact us or refer to our info pages for each individual gem type.