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Big Gem Stones

Understanding Large Gemstones

When we talk about big gemstones, we are obviously referring to large gems that are natural and not factory made. Manmade gems can be huge and even appear gorgeous to the untrained eye but, a natural gem is something that all gem lovers would prefer. Natural gems are mined from the earth, in their natural form they can be huge and weigh even a few kilograms. In technical terms gems when mined are referred to as 'rough' gemstones. They then go throug various phases and end up as cut gem stones. The point is that a rough gem that can weigh a kilogram, will not cut to a single gemstone. Once you take out the inclusions and foreign bodies that are in the rough gemstone, the size gets smaller and smaller. You then have to separate out the gem pieces at the point where there are deep cracks and fissures. So instead of getting one huge cut gemstone, you end up with hundreds or even thousands of smaller gems. We refer to the size of these finally cut smaller pieces when we try to classify them as big gems or small gems.

Let us understand how cut gemstones are weighed, if you are already aware of carat weights then skip this paragraph. Gems that are mined (rough gems) are sold in kilograms or grams. A kilogram as we all know is composed of 1,000 grams. Cut gemstones are generally weighed in carats (not Karats) and 1 gram is equal to 5 carats. So when you choose a small or large gem, the seller gives you a price per carat. Gems which are not very expensive are generally sold per piece. If you do get a price quote for a gemstone based on the piece rather than weight, you can ask your gem provider to check the weight and inform you about it. Then take the price per piece and divide it by the number of carats. You will then get the price per carat.

Defining a big gemstone: So how big should a gem be for it to classify as a large gem stone? The answer is not straightforward and an explanation will make it easier to understand. All gems are not priced equally and the availability of all gems is not the same. The planets gemstone resources are far more abundant in quartzes rather than in rubies, sapphires and emeralds. Infact some gems like tanzanite, are mined in only one location on this planet. The rarer a gem stone the more expensive it is and gems that are rare, are also found in smaller sizes. If you were talking about a one carat amethyst (a type of quartz), this would surely be a small size. But if you were talking about a diamond, a one carat stone can safely be defined as a large diamond. These are two extreme cases but are good examples to explain the issue. Another example would be to compare a blue topaz and a blue sapphire gem stone. A big blue topaz gemstone could be in the 20 to 40 carat range but, a good blue sapphire that is three to five carats could also be defined as a big gem stone. You will therefore need to understand the specific gem before deciding whether it is a small, medium or large gem. Your jeweler should be able to help you but, our support team at sales@kaisilver.com is always ready to discuss any gem or jewelry related issues.

Pricing of large gems: We mentioned above that, gemstones are generally sold by weight and price is quoted per carat. This is quite right but there is a small qualification to be made to this statement. Let us presume that you were talking about a ruby gemstone with a specific color and clarity. You might be told that the gem stone is priced at 500 U.S$ per carat and a weight check might show that the weight is 2 carats. A simple calculation would tell you that the price of the ruby gemstone piece is 1,000 U.S$. Now presume that the same color and clarity was required for a 5 carat ruby gem stone. You might expect the price for the gem stone to be 2,500 U.S$ since the price per carat was 500 U.S$. However this will not be true since the price per carat would jump from 500 U.S$ to probably around 1,000 U.S$. This is because ruby is a rare gem and larger pieces are more expensive (per carat). So this 5 carat ruby gem stone would cost you around 5,000 U.S$ for the piece. Keep this in mind when choosing a design for your large gemstone jewel. 

Big gems and treatments: Most gems that are mined are put through various treatments, gem manufacturers do this to increase the beauty, clarity and color of the gemstone. For example, all sapphires and rubies (more than 95%) are heat treated. Heat treating these gems is so rampant that even gemstone experts accept the treatments. However other treatments have slowly been developed, to enhance the beauty of blue sapphires. Surface diffusion is one treatment for blue sapphire that gives a lovely blue coating to the gemstone. So you might have a 5 carat blue sapphire that has severe color zoning and streaking. This basically means that the gem was cut larger than it should have been. Had the portions with color zoning and streaking been left out, the size of the resulting sapphires would be much smaller. If you had to do a surface color diffusion on this 5 carat sapphire it would appear to have a gorgeous blue color and almost no color flaws would be visible. The point is that color diffused blue sapphires should cost very much less as compared to similar (looking) gems that are naturally colored or just heat treated. So this color diffused blue sapphire with a weight of 5 carats should cost you no more than 500 U.S$ to 1,000 U.S$. But a natural heat treated blue sapphire with similar external appearance and a weight of five carats, could cost you around 7,000 U.S$ to 10,000 U.S$ for the piece. The subject of treating gems and the issue of acceptable and non-acceptable gemstone treatments, is a lengthy and highly technical issue. You will need to choose a reputed gem and jewelry provider to ensure that you get what you pay for.

Big gemstone jewelry: It is obvious that most large gem stones finally get set in jewelry. We have a few suggestions and bits of advice that will help you choose the right jewelry with big gems. Make sure that the metal weight for such large gem stone jewelry is sufficient and proportionate, to the overall gemstone and jewel dimensions. For example, a mens ring with a big 12mm x 10mm oval amethyst gem should ideally have a weight that is not less than 18 to 20 grams. We are aware that many jewelers peddle such mens rings with a low weight of 10 to 12 grams but, this compromise in weight will also mean a compromise in longterm durability. Another thing that you should keep in mind is the specific gem stone that you will be selecting for the jewel. Talking about the same mens amethyst ring with a large gem (12mm x 10mm oval), you might not want to retain the gem dimensions if you were choosing a ruby or sapphire. This is because even moderately good rubies and sapphires in this size can carry stiff price tags. It is very likely that large gemstone jewelry prices can be high when done in gold. If you find big gem stone gold jewels to be beyond your budget, consider getting the same designs done in sterling silver. A good custom jewelry provider can give you the same quality of design, craftsmanship and gem stones for gold or 925 sterling silver jewelry.

The images below are good examples of how no one standard 'big' gem stone size can be defined for all gems. It is not sales hype but rather an effort to educate you regarding what to expect in terms of size when referring to big gemstones.  

big sapphire gemstone, large pink sapphire gem
Opaque gems can generally be found in larger sizes as compared to transparent gems. This probably is because clarity and inclusions are not an issue when it comes to opaque gem stones. This is a big agate gem stone with size 26mm x18mm. Check out more details here. This transparent pink sapphire is a rare gem stone and surely classifies as a big gem. Considering that this is a good quality natural pink sapphire, the gem stone size of 10mm x 8mm and a proportionate weight of 3.5 carats establishes this gem stone as a large stone. Get details of this gem here.
big topaz gem stone, large topaz gems large sapphire, big ceylon blue sapphire gemstones
The London Blue Topaz gemstone shown above is huge, it is probably one of the largest gems that a casual jewelry or gem buyers will come across. Keep in mind that this a natural topaz gem and not a man made substitute. This big blue topaz gem weighs a whooping 40 carats and measures an impressive 20mm. Get the whole story here. This ceylon blue sapphire has a size of 10mm x 8mm and a weight of 3 carats. While this might not see like a large gemstone, you will find it in the big gems category as it is a blue sapphire and more importantly, the origin of this big sapphire is Sri Lanka (ceylon). It is not easy to find good quality ceylon blue sapphires in the above 2.5 carat size range these days, get details here.

Kaisilver is the world's leading online custom jewelry provider. Over 3,500 skilled craftsmen and artisans work on all Kaisilver jewelry orders. The same designs, gemstone options and craftsmanship is provided for gold and sterling silver jewelry. Direct access to over 250 million carats of gems is available through connections with miners and large gem manufacturers. You can buy just loose gems or request for complete custom jewelry to be produced with your choice of metal , design and gemstones. You can see some of our fine custom jewelry at http://www.kaijewels.com/ 

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