Evaluating Color of Gemstones by Using the GIA or Munsell Color Grading System

Although there are many and equally effective color grading systems in use today, the GIA or Munsell system is a good primer to start with. It utilizes a plastic set made up of 324 color pieces to serve as standard references. If a certain color is found missing from the system, interpolation can be performed to come up with more than 760 additional shades.

The GIA or Munsell system is made ideal for judging the color of gemstones because they are built with 3D plastic pieces that resemble faceted gemstones.

Elements of Color

The color of gemstones should be judged according to the three main elements:

Hue – This is the first impression we obtain from viewing colors. It is what makes rubies red, sapphires blue, emeralds green, and amethysts purple. Hues have a natural order and they are red, yellow, green, blue, and lastly purple. Numerous shades can be achieved by mixing together any two of these hues.

Chroma or Saturation – This element refers to the vividness, purity, strength, or intensity of a given color. Gemstones with low chroma are referred to as weak while those with high levels of saturation are called vivid or strong. Saturation of colored gemstones may be classified as the following in ascending order: grayish or brownish, slightly brownish or grayish, very slightly grayish or brownish, moderately strong, strong, and lastly vivid.

Value or Tone – This is what makes you think of red as light or dark red. Gray as well as black and white are referred to as neutral or achromatic colors because they don’t possess any hue. Colors with hues are referred to as achromatic colors. GIA uses a numerical system, with its written definitions, to evaluate neutral and achromatic colors alike. For transparent colored gemstones, however, only grades or tones two to eight are considered.

0 colorless or white

1 extremely light

2 very light

3 light

4 medium light

5 medium

6 medium dark

7 dark

8 very dark

Treatments Used for Changing Colors of Gemstones

When shopping for colored gemstones, another question you should definitely ask and one you couldn’t evaluate without a definite honest answer is if the color is natural or applied. There are several commonly used and accepted color treatments that are applied to gemstones in order to change their appearance like heat treatment, irradiation, dyeing, and straining.

Heat Treatment This is the most commonly utilized and one of the oldest treatments for modifying the color of gemstones today. This treatment may use temperature ranging from 100 degrees Celsius to more than 2000 degrees Celsius and improves color distribution as well as reducing visibility of flaws.

Irradiation Low or high electromagnetic waves or energy particles are used to change the color of a given gemstone. Like heat treatment, there is little remaining evidence that could clue a buyer to its use.

With irradiation, certain gemstones have their colors enhanced. Bleached, off-color pearls will obtain a darker tint. Brown or light yellow diamonds can become colored. Light yellow or colorless sapphires may turn yellow to orange, but the change could only last for days. Colorless quartz may turn into smoky quartz. Colorless as well as pale pink and dark blue beryl may become yellow or maxixe-type respectively. Time, light, and heat may, however, cause the color for treated beryl jewelry to fade.

Dyeing and Straining This is the major term used to refer to various techniques utilizing a foreign and differently colored substance to modify the color of a given gemstone. A combination of techniques, like dyeing and clarity enhancement for beryl, may be used to improve overall effects. In coating, the application of a second substance is only done on the surface.

Practice makes perfect so browse jewelry shops to familiarize yourself with the various signs that could alert you to the use of applications and treatments on gemstones.

]]> http://knowingjewelry.com/how-to-determine-the-price-value-of-color-in-gemstones.html/feed 21 http://knowingjewelry.com/tips-when-aiming-to-buy-rough-diamonds.html http://knowingjewelry.com/tips-when-aiming-to-buy-rough-diamonds.html#comments Sat, 07 Mar 2009 08:16:57 +0000 MS Prasaja http://knowingjewelry.com/?p=135 Diamonds are women’s best friends. The most important jewelry and accessories almost always have diamonds as gemstones. Diamonds are known as the hardest substance on the planet. They can’t always be cut and broken down easily. Diamonds are used to cut other diamonds.

Aside from that property, diamonds are considered as among the most important elegant substances on earth. The substance isn’t an element because it isn’t pure, but it is known to be a product of the pressure applied to carbon. Diamonds aren’t easily found in mines and it is very rare that explorers and miners are fortunate enough to find diamond mines.

Rough diamonds are diamonds in their unaltered state. Rough diamonds are literally rough because they aren’t yet cut and smoothed for jewelry purposes. Jewelers and designers strive to secure and acquire diamonds in their rough state. That is because they will cut the substance according to their design plan. They then shape the rough diamond according to the design and fit the stone to the jewelry they choose.

Jewelers aren’t the only people who regular buy rough diamonds. You could also strive to attempt to acquire such items. If you are aiming to customize your diamond jewelry according to your designs and preferred shapes, then, it is high time you buy rough diamonds. Here are some practical tips that will help you when buying rough diamonds on the market.

- Make sure to do transactions with accredited and popular sellers. Rough diamonds are still expensive even if they aren’t yet cut and shaped. Thus, expect to shoulder a significant investment on the purchase transaction. You should stay away from suspicious and unreliable sources because you might end up buying fake diamonds.

- Secure experts’ advice. If you can take an expert with you while doing the transaction, the better. Experts can easily tell whether the product is genuine or whether the price tag is practical and appropriate.

- Make the legal and necessary actions to ensure that your rough diamond won’t be replaced or altered when you bring it to a jeweler for customization.

Rough diamonds aren’t yet shaped and smoothed but they have the potential to be pricey. Rough diamonds are good buys because they are cheaper and are more practical. You can do whatever you like with these diamonds.