How to Tell If a Ruby Is Real: Natural & Treated Rubies

Last Updated on April 12, 2023 by Juli "Jewels" Church

Wondering if you have real or fake ruby on your hands?

You're in the right place. 

In this Learning Guide, I'll answer the following questions:

how to tell if ruby is real
  • What's the Difference Between Natural Rubies and Treated Rubies?
  • Where are Genuine Rubies Found?
  • What is Fake Ruby?

What are Natural Rubies?

A natural ruby stone is the red variety of the mineral corundum. They are beautiful gemstones. Corundum is the mineral species responsible for every colored sapphire gemstone out there. Ruby takes the place of what would be called red sapphire.

Rubies are a one of the four precious gemstones in jewelry. It's the birthstone for those born in July and an all around favorite stone for many gemstone jewelry lovers.

ruby crystals on matrix

credited: opacity

pigeon blood burmese ruby

Ruby gemstones are found all over the world. Various places produce red gems with different red hues. Myanmar (formerly Burma) produces the highly coveted pigeon blood rubies. Other notable countries producing gem quality include Afghanistan, Thailand, India, Madagascar, the United States and many others.

Natural Ruby vs Heat Treated Ruby

Heat treatments are given to many colored gemstones in order to enhance color. For most gemstones, heat treatments are normal and don't have a big impact on value. The gemstone industry agree it replicates the real process of rubies heating up and enhancing color by the earth.

Heat treatments aren't the only way to enhance ruby color. Many rubies can be irradiated to achieve better shades. Irradiation is permanent and undetectable by the average person. You should assume all natural rubies have been treated unless disclosed otherwise.

Untreated natural rubies are highly expensive. If they're from Burma, they're even more expensive. An untreated Burmese ruby can go for over $10,000 per carat.

burmese ruby price

Questionable Treatments

Heat treatments don't bring down the value of actual ruby. However, not all ruby treatments are heat treated. Rubies may receive treatment to enhance clarity or they may be glass filled. These kinds of treatments reduce value. Glass filled ruby is also considered fake to the general population.

glass filled ruby composite

A good way to tell a glass filled ruby gemstone from a heat treated ruby is by using the light to angle the stone. A glass filled ruby will exhibit flashes of red and orange at different angles. Similarly, glass ruby imitations are usually identifiable by their shades because red glass doesn't produce the hues like true ruby.

They may also be called composite rubies.

Natural Ruby vs Synthetic Ruby

The average person wouldn't be able to tell if they have a natural or synthetic ruby. Synthetic rubies are real rubies created in a lab.

Both natural rubies and lab created rubies get their red color from chromium impurities in the corundum crystal. Synthetic rubies produce bright red hues and consistent clarity. Jewelry stores like Kays, Zales, and Jared all have synthetic rubies in their cases.

loose synthetic ruby
lab created ruby engagement ring

So while some of these tests and indications may tell if a ruby isn't a fake ruby, they won't always tell you if it's a synthetic stone or not.

Ruby vs Pink Sapphire

A lot of people think real rubies are blood red and only that shade. Natural rubies can be various shades of red to hot pink colored hues. They can also be a dark shade of red. If the dark red color is too dark, it brings the value down.

This is where some gem dealers like to confuse you. Ruby stones can have reddish pink to purple hues. Pink sapphires were normally shown as a lighter shade of pink. They can range from peachy pink to hot pink.

So, where does the line lie between hot pink sapphire and pinkish red rubies?

pink sapphire engagement ring
reddish pink ruby engagement ring

The line my friends, is blurry. Gemologists agree that a pink sapphire would be a pinkish red color and a ruby could be reddish pink. However, color is in the eye of the beholder. Everyone views it differently.

What is Fake Ruby?

Mined rubies, heat treated rubies, and synthetic rubies are all real ruby gemstones. Any other gemstones or materials claiming to be ruby are ruby imitations. A fake ruby doesn't have the same physical, chemical, and optical properties as ruby. Fake rubies can also be real gemstones or minerals as well as manmade materials. 

almandite garnet

Almandite Garnet

red spinel

Red Spinel

red acrylic gemstones

Red Man-made Gem

Before red spinel was discovered, every red gemstone found was thought to be genuine ruby. The Black Prince's Ruby was misnamed in the 1300s and is actually a red spinel. They didn't discover true identity of the stone until the 1500s. By then, they couldn't change the name. The famous fake ruby remains on display in London.

Read also: Red Spinel vs Ruby

Synthetic spinel is easily produced and is often advertised as real ruby. Cubic zirconia and red colored glass can be faceted to pass for a ruby at first glance.

Real Ruby vs Fake Ruby: What's the Difference?

There a few indicators to help you tell if a ruby is real or not. You shouldn't rely on just one detail to tell if your ruby jewelry is real. You don't always need fancy equipment to tell real rubies from fake rubies made of red glass, red cubic zirconia, or red spinel.

The best way to tell fake rubies from real rubies is by observing the stone under a bright light source and with a jeweler's loupe.

Read also: Garnet vs Ruby


Real ruby has inclusions, or tiny flaws captured in the crystal as it was forming in the earth. Inclusions in ruby gemstones are called rutile or silk inclusions. When a real ruby is cut en cabochon, it may show asterism as a result of the rutile inclusions. Natural star rubies are desirable.

Highly included rubies have inclusions that can be seen with the naked eye. These are considered low quality. If it isn't cut well, it will be a dull stone. A high quality ruby stone still may have visible inclusions under high magnification.

Most rubies that are completely clear indicate the stones are fake stones, or they may be lab created. Actual rubies with high clarity go for very high prices. Anything claiming to be a "deal" on a real ruby gemstone is most likely fake or synthetic stones.

If the same crystal clear ruby is going for a very high price, you should consider its other factors to indicates its authenticity.

Mohs Scale

Most people who know about the Mohs scale assume it's the only factor for gemstone durability. They're misled about the "hardness" part. A gem's hardness rating tells us its scratchability.

The scratchability rating is important to a mineral because of dirt and dust in the air. Much of the dust in the air is actually quartz and other minerals. These minerals can scratch gemstone jewelry, especially if you're wearing it every day for years.

That's why there are some colored gemstones can't be worn as engagement ring jewelry. Corundum is one of the hardest gemstones. For rubies, only a diamond can scratch them. Diamonds are the hardest gems.

The scratch test is very effective to tell ruby's authenticity. It's not easily scratched, so you can attempt to scratch it using glass or a steel blade. If it's not damaged, it's more likely to be real.


There are some different tests you can perform to tell if you have imitation rubies. Some of these can be performed by observing with your eyes or through a jewelers loupe. Others can be tested by using the stone itself against another surface.

However, these factors may only indicate you have a fake one. If you are trying find natural rubies, you should only buy from a retailer with a legitimate gemstone certificates to reveal if the ruby is real.

This is the only foolproof way you can distinguish an untreated natural ruby from a treated natural one.

Hopefully you've gotten some helpful information to help you tell the difference between real ruby and artificial rubies. Some of these may eliminate your search without needing a certificate or going to a reputable jeweler.

However, I highly recommend buying loose gemstones with an official certification from professional gemologist or grading lab.

Remember, most tests will eliminate the authenticity of gems. It will not always tell you which stone or materials the ruby stones are made of.

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