Gemstone Value: 5 Flaws that affect the Price

Like all naturally occurring gemstones, emeralds and sapphires too have their own set of physical flaws that affect the quality, clarity and price of the gemstone. As emeralds and sapphires are formed under intense temperature and pressure under the earth surface, they are susceptible to severe faults. Often regarded as the “birthmarks” by gem experts, the emeralds and sapphires are inflicted by major blemishes when compared to the diamonds.

For buyers looking for top grade emeralds and sapphires, here are 5 things to do to get maximum worth from cut gemstones.

1.  Crystal:

The inclusions are extraneous constituents that enter the crystal lattice during the formation of the gemstones. It is hard to detect a crystal flaw by the naked eye but can be picked under a 10x magnification microscope. Sometimes the gemstones collect another gemstone inside its crystal structure leading to the formation of lighter or darker inclusions. Highly undesirable, the crystal flaws can be removed by heat treatment; however, it is mostly cut into smaller briolette to save the cost of material.

2.  Cavity:

Emeralds and sapphires acquire flaws in the form of cavities that look like a crevice. The cavity usually appears due to the cracks along a straight line running parallel to the crystallographic planes. These fault lines lead to the formation of cleavages which can break away further if force is applied on them. They should be avoided especially for setting on prongs and rings.

3.  Bearding:

The flaws appear during gem cutting when the angle of cut is too close to the girdle. Also called “dig marks”, bearding is particularly visible in light colored gemstones. They are blamed for further reducing the brightness of the deep colored sapphires and emeralds. It is possible to clear these flaws by polishing and dyeing to improve the luster.

4.  Needles and cloud:

Rules or needle inclusions are common blemishes that impact the value of a natural gemstone. If the gemstone is set to be cut into fancy shapes or faceted cubes, the needles and cloud devalue the price of the gemstone by 75%!

When two or more needles occur too close inside the crystal, they form a cloud-like haze. These formations are undesirable, and hence largely avoided in the commercial market.

5.  Carbons:

Owing to the presence of hydrocarbons in the earth’s crust, the naturally occurring gemstones may acquire carbon impurities inside their crystalline structure. Much like diamond gemstones, emeralds and sapphires too lose their value if carbon spots appear on the surface. The carbon flaws may exaggerate the cleavage if the gemstones are heated artificially. The carbon spots can be picked with naked eyes.

What to do if you find gemstones with these flaws?

The gemstones are graded into different categories based on the kind of display they exhibit after the polishing process. Buyers must check the tag of the gemstones for the following mentions:

•  Excellent
•  Very Good
•  Good
•  Fair
•  Poor

If you anyhow end up with a gemstone that is good, fair or poor in quality, the only option left is to cut the gemstone into Fancy shapes and try to retain the brilliance.

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