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Basics about Buying Gemstones

Updated on June 29, 2016

Joined: 5 years agoFollowers: 500Articles: 154

Get Glitzy with Gems

One of the first things people notice when they visit my home are the rocks I keep on display here and there throughout my house. I started collecting rocks as a little girl. I was fascinated by the variety of colors and shapes. Quartz crystals weren't so tough to get my hands on, and they were almost as good as a diamond to a pre-teen like me. I could gaze with wonder at how something so perfectly shaped could have developed entirely by natural forces.

Although I'm grown now, I still enjoy the basic stones I gathered as a kid, but my tastes have expanded to include a love of gemstones. If my pocketbook would permit it, I'm pretty sure my walls and windows would be unlike what you've ever seen in a house before, but I digress. Although I'm not a gemologist, I was surprised at how affordable some of the gems I saw at the huge annual Tucson Gem and Mineral Show were, and how much more expensive a similar gem could be.

Since then, I've learned a lot about what factors influence prices of gems. In this second article in my series on gemstones, I'll be discussing some of the factors you should take into consideration if you're in the market for gemstones, gemstone products, or jewelry. The science of gemology is complex, and I'll be assuming you're like me - fascinated but not planning on becoming a science expert before you make your first purchase!

I'll give you general guidelines that are more in depth than you'll find on a jeweler's site aimed at convincing you to buy at high markups, but not so much information that you'll feel like you're in science class trying to figure out how to figure out what "birefringence," "pleochrism," and "specific gravity" mean.

Ready to get started?

Stones May be Purchased in Different Forms

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These popular fancy cuts are also used on other semi-precious stones like emeralds, rubies, and sapphires. Can be bought wholesale or retail.Arrowheads are examples of carved stones, though they wouldn't be considered gems. Carvings can be purchased wholesale or retail. Would you recognize these loose, rough stones as emeralds? These types of stones are usually purchased from wholesalers.These stones have all been polished. The larger piece is a loose tumbled stone, the small ones only polished and now a necklace. Beads are often sold in these two forms. These forms can be found at wholesalers or retail gift shops.Amethyst and lapis lazuli. The amethyst is shown here as untreated (top left) and polished forms (bottom left.) This lapis was polished and tumbled.Most faceted gems are sold to consumers already placed in a setting, but can be purchased wholesale, too.Cabochons are widely available from retail jewelers, on belts, and more. This is an inexpensive way for amateurs to break into gem cutting, too. There's a high demand for cabochons in both retail and wholesale markets.Ornamental stone, like this marble carving at the Tomb of the Unknown Soldier, can be elaborate or simple, but is generally found with retail and specially ordered products.
These popular fancy cuts are also used on other semi-precious stones like emeralds, rubies, and sapphires. Can be bought wholesale or retail.
These popular fancy cuts are also used on other semi-precious stones like emeralds, rubies, and sapphires. Can be bought wholesale or retail. | Source
Arrowheads are examples of carved stones, though they wouldn't be considered gems. Carvings can be purchased wholesale or retail.
Arrowheads are examples of carved stones, though they wouldn't be considered gems. Carvings can be purchased wholesale or retail. | Source
Would you recognize these loose, rough stones as emeralds? These types of stones are usually purchased from wholesalers.
Would you recognize these loose, rough stones as emeralds? These types of stones are usually purchased from wholesalers. | Source
These stones have all been polished. The larger piece is a loose tumbled stone, the small ones only polished and now a necklace. Beads are often sold in these two forms. These forms can be found at wholesalers or retail gift shops.
These stones have all been polished. The larger piece is a loose tumbled stone, the small ones only polished and now a necklace. Beads are often sold in these two forms. These forms can be found at wholesalers or retail gift shops. | Source
Amethyst and lapis lazuli. The amethyst is shown here as untreated (top left) and polished forms (bottom left.) This lapis was polished and tumbled.
Amethyst and lapis lazuli. The amethyst is shown here as untreated (top left) and polished forms (bottom left.) This lapis was polished and tumbled. | Source
Most faceted gems are sold to consumers already placed in a setting, but can be purchased wholesale, too.
Most faceted gems are sold to consumers already placed in a setting, but can be purchased wholesale, too. | Source
Cabochons are widely available from retail jewelers, on belts, and more. This is an inexpensive way for amateurs to break into gem cutting, too. There's a high demand for cabochons in both retail and wholesale markets.
Cabochons are widely available from retail jewelers, on belts, and more. This is an inexpensive way for amateurs to break into gem cutting, too. There's a high demand for cabochons in both retail and wholesale markets. | Source
Ornamental stone, like this marble carving at the Tomb of the Unknown Soldier, can be elaborate or simple, but is generally found with retail and specially ordered products.
Ornamental stone, like this marble carving at the Tomb of the Unknown Soldier, can be elaborate or simple, but is generally found with retail and specially ordered products. | Source

Types of Rocks

In the coming months, I'll be writing about specific types of stones, but for now, let's start with the most basic piece of information you'll need to understand if you want to become an astute gem collector or jewelry purchaser - most gems are rocks of a sort, but not all rocks are gems.

The type of gem you'll buy could fall into a couple of different categories that sometimes overlap with each other:

  • Precious
  • Semi-precious
  • Ornamental
  • Synthetic (like cubic zirconia)
  • Organic (pearl, for instance, is not a mineral)
  • Enhanced (natural or synthetic gems may undergo special treatments to produce a desired effect.)

All of these types of gems may be sold in a variety of ways:

  • Rough stones (untreated)
  • Loose finished stones (may be treated, cut, polished, faceted, or rough)
  • Set stones (already placed in a setting of some sort, such as a ring

The gems themselves will have a certain look to them

  • Faceted stones have been cut in a way designed to bring out their brilliance.
  • Polished or tumbled stones are usually either ornamental or semi-precious stones. They're unfaceted.
  • Cabochons have a flat bottom and domed surface.
  • Carved stones may be in a particular shape or have shapes and designs cut into them.

Faceted stones can have many unusual cuts to them. Some faceted cuts are very popular, like "round cut" or "princess cut" diamonds. The photos below reveal the many different ways gems can be sold by wholesalers and retailers.

Gemological Institute of America Diamond Grading Methods

4Cs of Gemstones

Although there is no standard grading system for most gems, diamonds do have a classification system based on the 4Cs set forth by the Gemological Institute of America. The GIA's grading standard has been adopted industry-wide throughout the world. By understanding the standards used for grading diamonds, you'll be better able to judge whether a gem is worth its asking price. This video explains the in-depth methods used by the GIA. While you and I cannot replicate their methods to an exacting degree, it's certainly possible to develop a sharper eye for your own gems.

The 4Cs refer to a gem's

  • Color
  • Cut
  • Clarity
  • Carats (weight)

Whenever you're considering buying a gemstone of any type, remembering these 4C's will ensure you don't overlook something important, so let's discuss each of these characteristics a little more.

These three stones are all jade, even though only one has the green hue we normally think of for this ornamental stone.
These three stones are all jade, even though only one has the green hue we normally think of for this ornamental stone. | Source
The less color a diamond has, the higher its value will be, but even highly colored diamonds can make beautiful jewelry.
The less color a diamond has, the higher its value will be, but even highly colored diamonds can make beautiful jewelry. | Source
These samples of corundum could be used for gemstones, perhaps, but without a good combination of the 4Cs, would be more likely to be used for industrial purposes.
These samples of corundum could be used for gemstones, perhaps, but without a good combination of the 4Cs, would be more likely to be used for industrial purposes. | Source

Gemstone Colors

Tourmaline is known for having multiple colors. How rich and saturated the color is can greatly affect value.
Tourmaline is known for having multiple colors. How rich and saturated the color is can greatly affect value. | Source

Did you know over 200 different colors of diamonds have been documented? Stones get their color from the kinds of elements they contain. Even a small variation in a stone's chemical composition can produce a change.

While diamonds with no color at all are the most highly valued, other stones gain value by having more color. Emeralds, for instance, will likely cost more when they are a deep green than if they are pale.

Corundum is the name of a transparent crystal that we call by different names depending on whether other elements got infused with the aluminum oxide it's made of. Rubies are corundum that was affected by the presence of chromium, while every other chemical color change would result in the stone being called a sapphire (even if it's yellow or green.) Impurities like the dark spots shown in the near colorless sample of corundum are common, and when there are too many, the stone loses its appeal as a gemstone and instead, may be used for other industrial purposes like making sandpaper.

Some stones are devalued by the presence of other colors, like when a deeply hued amethyst is riddled with quartz, while some gain a great deal of value by having multiple colors that are well placed, as seen with star sapphires or tourmaline.

Always look at a gem against a white background and use both natural and artificial lighting if possible. Jewelers have often used contrasting colors to make a gem look more appealing. Consider whether the color is rich and true or pale and lackluster. Hue, saturation, and tone are all important to determining value of a particular stone. Having said this, though, let me also say that if you love it, don't reject a stone based purely on color. Today, "white turquoise" is a popular jewelry choice, but years ago it would have been rejected for its color!

Smithsonian Handbooks: Rocks & Minerals (Smithsonian Handbooks)
Smithsonian Handbooks: Rocks & Minerals (Smithsonian Handbooks)

Check out this handy guide if you enjoy natural stones as well as gems and want to learn more about how they were formed.

 
DUSIEC Jewelry Diamond Tester Gemstone Selector Analyzer II Gems Gemstone Tester LED Tool
DUSIEC Jewelry Diamond Tester Gemstone Selector Analyzer II Gems Gemstone Tester LED Tool

An inexpensive tester that distinguishes between diamonds and cubic zirconium. Now beginning gem collectors can distinguish between real and non-natural stones easily and quickly. Highly rated.

 

Cut Gems

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The cut of a diamond refers to more than simply what shape it looks like. The GIA standards shown in the video above reveal that there are mathematical ratios to determine "ideal" angles and depths of the gem's surfaces.

Other gemstones may be faceted to look similar. The ring on my finger in the first series of photos shows a very basic cut. Different types of angles and surfaces can make a gem reflect more light and brilliance.

While determining a gem's cut with any precision is best left to the experts, as a buyer of gemstones you can evaluate a few things on your own. Look for a high degree of:

  • Sparkle - a well cut gem will sparkle and capture attention with the way it reflects light.
  • Brilliance - some stones aren't faceted or cut, but I will include them here anyway. Polished or tumbled gems are a terrific way to learn about ornamental stones and can make some beautiful jewelry, too. Look for whether their beauty is reflected well by the way they have been mounted or presented.
  • Fire - though this is often masked in darker stones, light stones like diamonds, opals, and even aquamarine will let you see a prism of colors as they break down light into the colors of the spectrum. When buying light colored stones, evaluate whether you see colors and determine if a lack of color is due to a poor cut or the type of stone.

As I mentioned above, if you love a stone, don't get stuck on its cut. Many beautiful gems aren't cut perfectly. What it lacks in vibrancy will also be lighter on your pocketbook, so go with what you like as long as you feel it's available at a fair price.

What Is Clarity?

When it comes to a gem's clarity, it's important to understand that while the presence of other minerals gives gems their color, most have imperfections. A piece of sediment that was absorbed as the gem was forming or a microscopic fracture can affect value.

For some gems, like organic amber, certain ornamental stones, and fossils, inclusions can increase value. However, when looking at transparent, cut gems, they're likely to decrease value. A 10X magnification loupe like the one shown here is valuable for detecting these imperfections.

When looking at a stone for impurities, it's also important to note that all stones are not graded the same. Aquamarine, for instance, is not graded the same way as a tourmaline or emerald that has a darker color that can mask the impurity. For an overview of what to look for check out this chart.

Tip: Learn about gem values by visiting gem shows, jewelry shops, and browsing price guides.

Carat Weight

The last C today is carat weight. A "carat" simply refers to a weight of 200 mg.

Larger gems tend to be worth more than smaller ones, of course, but if they're suffering in one or more of the other Cs, it's possible for a larger gem to cost less than a much smaller one of high quality.

Because there's no set standard and the gemological world is constantly changing, I would encourage you to base your decision to purchase on what you like and what you can afford. Find pieces you like and use these principles to figure out what is the best value for you. I happen to prefer chocolate diamonds over the much more expensive ones, which means I would spend the same amount for a higher quality chocolate diamond than for a purer, colorless diamond. I'd get much more use out of my choice and enjoy it more as I did.

I promised you I wouldn't get too technical, and I think I've kept my promise. At least I hope I did. Please let me know what you think in the comments below, or by sharing this article with others you think would enjoy it.

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  • jellygator profile image
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    jellygator 3 years ago from USA

    Thank you, Angara!

  • jellygator profile image
    Author

    jellygator 3 years ago from USA

    Glad to hear you found this useful, Teaches! I plan on doing some more articles on gemstones soon. There is just SO much to know!

  • teaches12345 profile image

    Dianna Mendez 3 years ago

    Interesting article on gemstones. I didn't realize jade came in different colors and the color on diamonds was less value. I now now what clarity means as well. Thanks for the education.

  • jellygator profile image
    Author

    jellygator 3 years ago from USA

    Thank you, Rkwebs!

  • Rkwebs profile image

    Rajnesh kumar 3 years ago from India

    awesome information about Gemstone

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