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Gemstones

Why are some gemstones more valuable than others?

Have you ever wondered why a diamond is the most expensive one and others, not less beautiful, are much more affordable?

There are several characteristics of minerals which make stones precious and influence the price. These include hardness of the mineral, its rarity and translucency.

Hardness

The hardest minerals are called precious stones, i.e. diamonds, rubies, sapphires and emeralds. All others are semi-precious. The harder the stone does not necessarily mean the more expensive it would be. The high quality tsavorite may be more expensive than the low quality emerald. But due to the fact that hard gemstones are beyond time, they could be a perfect option for investment.

Rarity

Amethyst had been a greatly valuable gemstone till the huge resources were found in Brazil and the price fell down. The same holds for the opposite situation when the significantly big mine of a gemstone is running low, the prices are going up.

4 C: Color, Clarity, Cut, Carat weight

Diamonds have a generally accepted grading system for all four characteristics - color, clarity, cut and carat weight. Any slight difference is easily assessed. Grading and pricing of gemstones is not that simple though and greatly subjective.

Color is a predominant characteristic for the price of the stone. Around 50 to 70% of the gemstone value depends on its color. While appraising the color, lightening should be taken into account. Red color stones look better in incandescent light, whereas blue ones - in the daylight. Hue, tone and saturation combined together form the color of a gem. Depending on the mineral itself, some hues might be rarer than others, thus more valuable.The optimal tone for a good quality stone is medium, i.e. any deviation to the darkness or lightness of the color decrease the value of a gemstone. Since saturation of the color leads to a darker tone, the best pieces have a high level of saturation but not the highest one.

In most of the cases the clearer the gemstone, the better. However, there are some occasions when certain inclusions increase the price and are more desirable than a clear stone. Thus, horsetail inclusions in a demantoid or the special texture of Kashmir sapphires are increasing the value of the stones. Since all minerals have different forming processes in nature, some of gems are hardly clear while others have often no inclusions. Hence, the pricing depends on the type of mineral and on the rarity of clear samples.

Cut is another quality of a gemstone to be considered while evaluating its price. This complicated characteristic greatly affect the color of a stone and therefore its value. One of the factors to consider here is the ability of a gem to return the body color back to the eye and the symmetry.

The last but not the least is the carat weight of the gem. This feature is easily assessed and depending on how common big sized minerals are in nature, the price rises gradually or sharply with the size of a gemstone.

What are synthetic gemstones?

Synthetic sounds fake for the most of us. But is it really so in the case of gemstones? Is jewelry made with synthetic gems something like a counterfeit good?

Our subjective judgment in this case is not quite true. Made in laboratory synthetic stones keep all the qualities of the natural gems, i.e. they have the same chemical, optical and physical characteristics. Moreover, since those pieces are made by human beings and not by nature, it is possible to create ideal gemstones.

Since 19th century people are producing synthetic gemstones. At the beginning those were for industrial application but not for jewelry. Now they are widely used in all areas.

Basically there are two ways to create a synthetic gemstone - using a melt or a solution to grow crystals. The former is easier, faster and therefore cheaper, and the latter takes a lot of time and thus is more expensive. Not all the methods could be used for producing different minerals. Hence, flame infusion and crystal pulling - both of which are using the melt as basis, - are applied to produce synthetic corundums, spinels, garnets, alexandrites and chrysoberyls. Another two using the solution - flux and hydrothermal growth - can be utilized to create a synthetic emerald, ruby, sapphire, alexandrite, spinel or quartz.

To sum up, having the same level of quality and preserving their major characteristics synthetic gemstones are not sharing rarity of natural gems and therefore are not that expensive.