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How can I Identify a Real Gem?

Harriette Halepis
Harriette Halepis

In most cases, the only reliable way to identify a real gem is to either have extensive training as a gemologist or a jeweler or to have access to intensive laboratory tests. These options aren’t always practical for the everyday shopper, but knowing a few tricks and tips can make your search for a legitimate stone much easier. One of the best places to start is to study the gemstone’s color spectrum and look at the arc of colors it produces in response to light. Real stones usually display a rainbow that will reflect on nearby walls and ceilings. Doing a bit of research on the characteristics of the specific stone you’re after will also help, and getting a professional opinion is almost always a good idea. It’s also really important to take your time, and not rush into a purchase decision based only on appearances.

Color Test

A jeweler can identify if a diamond ring is real or fake.
A jeweler can identify if a diamond ring is real or fake.

Most real gemstones will produce a full spectrum of colors when exposed to light, sunlight in particular. In order to see what colors the gem you’re considering can produce, hold it up to any kind of light. By placing the stone close to your eye and tilting it, you should be able to see a variety of colors. A real gem will produce a rainbow of colors; stones that do not produce anything are frequently fake. This test isn’t definitive, though, and some stones, particularly those with very dense, deep coloring or those that haven’t been polished completely, may not respond. This doesn’t necessarily mean that they are illegitimate. If a stone does not create small bits of color, the best thing to do is to put it through another test, preferably one specific to the stone at issue.

Know Your Stone

A shopper can ask a seller for a gemstone's certificate of authenticity.
A shopper can ask a seller for a gemstone's certificate of authenticity.

There are many different gems, from diamonds and rubies to sapphires, emeralds, and more, and each has its own unique characteristics. Determining the real from the synthetic often takes a deep understanding of exactly what the genuine article should look like. It’s important to pay attention both to physical attributes and geographic or place indicators.

Costume jewelry uses fake gems.
Costume jewelry uses fake gems.

Take the time to find out about the qualities of the stone you’re seeking, everything from color to size to common weight. If your stone does not have the same specifications, you may not have the genuine article. Asking about origin can also be helpful. Certain stones only come from specific geographical locations, so something that seems to come from an unusual place may not be real.

Knowing something about how real gems are processed can also be helpful. You can usually get this information by asking a jeweler or gemologist whether or not any treatments have been done to the stone in question. Since many different treatments can turn a regular stone into a shiny gem impostor, purchasing a stone that has been treated with a laser or heat is not often a wise idea. Real gemstones are often cut and polished, but most have not gone through any other treatments.

Importance of Documentation

If you are shopping for an expensive gemstone, it’s often a good idea to ask a seller whether or not you can view the stone's certificate of authenticity. In most places, all gems “of worth” — which is to say, any gems that have significant value — are accompanied by a certificate of authenticity. If the stone you are considering purchasing does not have a certificate, find out if you can have the stone appraised prior to purchase. Any reputable jeweler should allow an independent appraisal without argument.

Take Your Time

It’s usually a good idea to take your time when shopping for gemstones. Look at a few stones before settling on one to get a feel for the market. Backing off can make counterfeit sellers nervous, and may also give you the chance to see if the price being asked is fair or normal in your region. Far too many people rush into purchasing a stone that has a good price and the guarantees of the seller without doing any investigating of their own. Real gems may be hard to spot, but with a bit of knowledge and preparation you should be able to distinguish the perfect stone from a synthetic rock.

Discussion Comments


Can you make an article telling us what tests to do on Carnelian to see if it is real or fake,and not just stones in general?


To check if a gemstone is genuine, wrap a strand of hair around it. With a lighter/match, try to burn the hair. if it doesn't burn, it's genuine. If it does burn, it's fake. I tried it on my carnelian and my mum tried it on her agate, both were genuine. and both strands of hair burnt and stunk the place when burnt afterwards.


Is there such a thing as smooth, sky blue diamonds?


When it says it's genuine topaz, is it real or fake?


How can I check real gems or semi gems at home?


a fake gemstone will not scratch corundum (ruby and sapphire). You can buy non-gem quality rough stones at rock and mineral shops from $5 to $15 if you want test. Look up the Mohs hardness scale. Diamond is a 10 (hardest) and will scratch anything below it, including corundum (9). Corundum will scratch everything except a diamond.


If you are planning on purchasing an expensive gem ring or other piece of jewelry, I would advise buying something that is certified by an independent gem lab like the GIA, AGL, or EGL. These gem labs will give consistent grades and will detect fakes or altered stones. Getting a certified stone will also protect the resale value of the stone, but be aware; these grading reports are never appraisals. They only verify the characteristics of a stone. What you pay will depend on the market, and the rarity of a certain type of stone. You can find similar stones for very different prices depending on if you purchase form a wholesaler or a brick and mortar chain.

Any certificate of authenticity from a store is virtually meaningless because it is biased by nature. The only thing that the store should be able to provide would be a Kimberley Scheme certificate. If you need an appraisal, see an independent appraiser who will give you an unbiased appraisal of the stone.


@ Anon132416- Most diamond fakes are actually synthetic stones, not diamonds. Sometimes people try to pass moissonite (not sure if my spelling is right) as genuine high quality diamonds, and it can be very hard to tell the difference. A glass gem will not likely cut glass because they are of the same hardness, but certain types of glass can be softer than others leaving scratches. Most fakes however will cut glass so this is not a valid test to see if a diamond is real.

Most jewelers you go to will have a small laser like machine that can tell most real diamonds from fakes. They do not, however, tell if a diamond has been treated or filled. There is plenty of technology available that can make an inferior gem look precious.


will a fake glass diamond still cut glass?

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    • A jeweler can identify if a diamond ring is real or fake.
      By: habrda
      A jeweler can identify if a diamond ring is real or fake.
    • A shopper can ask a seller for a gemstone's certificate of authenticity.
      By: elen_studio
      A shopper can ask a seller for a gemstone's certificate of authenticity.
    • Costume jewelry uses fake gems.
      By: FedeCandoniPhoto
      Costume jewelry uses fake gems.