July 10, 2023
Recognize genuine gemstones

How to recognize genuine gemstones?

When buying jewelry or gemstones, as well as evaluating estate, it is important to know if it is genuine or not. Worked or treated or man-made gemstones can look just like natural, untreated ones, but are less expensive and have no lasting value due to their naturalness and rarity of occurrence.

The purpose of this article is to point out what the difference is between "real" and "fake" gemstones, how to find out, and where the differences lie for quick and easy identification. In the end it is often not easy for the layman to get a 100% statement, then the expertise of a gemologist or a certificate from a gemological laboratory is the best advice to know exactly what gemstone it is, if and how it is treated and where it comes from.

Fake gemstones look beautiful and are attractively priced, but they never have any substantial value because it is just not natural. It is important for you to know what you are being offered or facing, so feel free to read our handy guide with some simple tips and recommendations.

Colorless quartz can be faked to look like emerald and ruby
Colorless quartz can be faked to look like emerald and ruby
(source: GIA)

Common types of fake gemstones

Natural gemstones are precious treasures of nature due to their rarity. For many people, stones from direct nature are too expensive. That is why gemstones are often counterfeited, which means "imitated", "treated" or artificially produced.

A distinction is made between "genuine" and "fake" gemstones. Counterfeit gemstones is fake gemstones. Only natural gemstones are genuine gemstones. In order to distinguish more precisely the terms, it is important to distinguish and explain more precisely the following 3 categories:

1. Synthetic gemstones

2. Imitations

3. Treated gemstones

Synthetic Gemstones

A gemstone synthesis is a crystal chemically identical to the natural stone, made in the laboratory.

Because of their value, especially the high-value gemstones such as diamond, ruby, sapphire and emerald are produced artificially. For example, in the nineteenth century, the French chemist Verneuil developed a special furnace that allowed him to make large crystals of corundum from clean alum The basic material of ruby.

Unfortunately, it is not obvious to the untrained eye and the layman whether it is an artificial production, a synthesis, or a natural stone. Experts can help and in borderline cases a laboratory expertise is always useful. However, in the case of very fine qualities, which appear flawless and are very favorable in price, one should become thoughtful.

These faceted cubic zirconia look similar to a real diamond to change
These faceted cubic zirconia look similar to a real diamond to change
(Source: GIA)

Imitation stones are often made of glass, plastic, or synthetic resin. For example, as an imitation of amber is often used plastic and synthetic resin. You can recognize a real amber when it sinks to the bottom in fresh water and floats on the surface in salt water. Also, plastic can be "peeled" by the soft structure and scratches quickly appear on the surface. Molten amber is also often filled with dead insects or smaller animals such as scorpions or lizards. Real amber with natural inclusions simply costs significantly more.

The advice here is also to seek out a reputable seller with expertise, ask for a gemological certificate if necessary, and just also to be suspicious of corresponding prices, which are not realistic for real gemstones anywhere in the world today.

Imitated and treated spinel in all different colors
Imitated and treated spinel in all different colors
(source: GIA)
Treated gemstones

Treated gemstones are basically natural gemstones that have been treated, enhanced or optimized in some way to improve their appearance.

Types of treatments on gemstones include:

• Heating (not subject to labeling).

• Irradiation (subject to labeling)

• Dyeing (subject to labeling)

• Stabilizing (subject to labeling)

• Reconstruction or gluing (subject to labeling)

Note on all treatments subject to labeling:

Except for heating, the other treatments are all subject to marking, which is mandatory for the seller to indicate in the sale according to the international CIBJO rules for gemstones and jewelry. Treatments that require marking significantly alter the natural gemstone, by these significant effects can no longer be called a natural stone in the strict sense. This has a significant impact on its price and value, as well as its performance.

Therefore, our advice, mark treated gemstones are like costume jewelry, it may look good at first glance and is cheap but has no intrinsic value and especially no resale value no matter how big or beautiful the gemstone may be.

Note on heat treatment (not required to be labeled):

Heating gemstones has a special role because most gemstones are created by pressure and heat in the earth, and this form of color and purity enhancement has been done for over 2000 years.

It is considered common and usual in the market and therefore not subject to labeling for a natural gemstone. However, the seller should verbally point out that gemstones can be heated, or thermal treatment is a common treatment in the market for many types of gemstones.

Recognizing genuine gemstones is not always easy
Recognizing genuine gemstones is not always easy
(source: GIA)

Identification of genuine gemstones

How to identify the gemstones? We would like to present here 4 proven methods.

Method 1: Hardness test - how to determine whether a stone is a gemstone.

It should be noted that each mineral has a certain hardness. This parameter is described by the 10-step Mohs scale, in which the diamond, as the hardest stone, occupies the highest place 10. The hardness of rubies, sapphires, emeralds, and other gemstones can be determined using the Mohs table and the readings from a handheld meter.

Inexpensive meters are available everywhere, showing the hardness of minerals on a scale of 1 to 10. However, unprofessional instruments often cannot be calibrated, so the test result is not always reliable. If you want an accurate analysis of the hardness and properties of a mineral, a gemologist should be consulted. The expert will use a refractometer and accurately estimate the value of the stone.

Method 2: Color and light analysis

When we find a beautiful mineral on the ground or receive a colorful pendant as a gift, the question is which stone it is and how much it is worth. One can do a simple test at home to find out more about the authenticity and value of a mineral. This is because a magnifying glass can be used to check what color the stone is and how sunlight or artificial light passes through it.

A gemstone usually has a very intense color and a high refractive index. How do you recognize a stone in a ring? A natural mineral rarely has a perfect, uniform and perfect color. Light passing through the interior of a gemstone will split, may create a shimmer, scatter the color, or flicker. Artificial stones and zircons, on the other hand, are characterized by the fact that light rays pass through them easily. The color of imitation minerals is usually uniform, without cloudy streaks or inclusions, i.e. particles of other crystals, cracks, bubbles.

In the case of valuable gemstones, only an expert can be recommended who can perform not only microscopic analysis but also spectroscopy, this is usually done in a gemological laboratory to have absolute certainty.

Method 3: Heat testing at home - to distinguish between diamonds and synthetic stones

There are several ways to identify gemstones at home, even if you do not have a magnifying glass or other tools at hand. One of the easiest methods to distinguish diamonds from glass and crystal is the temperature test (heat test). How does it work? Simply place the stone in sunlight or white water. Alternatively, you can direct warm air from a hair dryer at the stone. The heat will cause the man-made materials to warm up, while the diamond will maintain a constant, unchanging temperature.

Method 4: Ask a gemologist or for a gemstone certificate

A layman cannot tell the difference between colored glass and ruby or cubic zirconia and diamond. How can you determine the value and quality of a gemstone? A gemologist is a mineral identification specialist who has advanced knowledge and tools to determine the type and value of a stone. A gemologist will thoroughly examine the stone using professional equipment.

When valuing gemstones, an expert opinion is useful, especially for insurance value. For a detailed examination of the gemstone, a gemological laboratory is useful for certification, or an expert opinion or gemstone findings report.

A gemological report is undoubtedly the best way to identify a genuine gemstone. It should also be remembered that not every jeweler or goldsmith is a gemologist. If you want to get a sound, reliable appraisal, you need to see an expert, this is the safest way and the best advice.

Fake gemstones look confusingly similar to real ones, an expert opinion is crucial for a reliable assessment
Fake gemstones look confusingly similar to real ones, an expert opinion is crucial for a reliable assessment
(source: GIA)

Popular gemstones and how to identify them

You can usually identify uncut gemstones by the fact that they often have a less vibrant color and a fairly rough appearance. But what about worked stones? To recognize a real gemstone, you need a lot of feeling and even more experience. If you have many gemstone, you know how it feels in your hand and on your skin. In the end, you can always ask a professional for advice, but still, there are some things you can look out for yourself as well:

• Price-Quality Ratio

• The way the stone feels to the touch

• Inclusions and bubbles

Tips for buying genuine gemstones

For buying gemstones, you should pay attention to some points in order not to be deceived, because you need to know what you are buying, and only genuine gemstones have their value in addition to their beauty.

When buying gemstones, one should follow these tips:

• The 4C's (Carat, Color, Clarity & Cut)

The evaluation of gemstones and their value depends significantly on their size, color intensity and color gradation, its clarity without visible inclusions, and the proportions and aesthetic symmetries of the cut for best brilliance.

• Genuine or synthetic?

Genuine is always natural, a product of nature. Synthetic is always artificial from the laboratory, arbitrarily producible without an intrinsic value.

• Independent certificate

Special gemstones should be examined in a gemological laboratory to document the criteria of treatment and origin, as this has an impact on the value.

• Price depending on the type of gemstone

The value of a gemstone depends on its rarity and beauty. Therefore, one should compare and choose for himself the perfect gemstone at an attractive price-quality ratio from an expert.

• Value depends on the color

The color of colored gemstones especially sapphire, ruby, emerald is the most decisive factor for the value and beauty of the gemstone.

• Clarity & Special Inclusions

Best brilliance and shine is obtained from a gemstone with as few inclusions as possible, this looks much more attractive and increases its value if no visible inclusions are visible to the naked eye.

• Seriousness and expertise of the seller

Buying gemstones and gemstone jewelry is always a matter of trust. Contact a professional who has the expertise and network to offer you the finest stones at an attractive price.

The best thing is always ask questions, questions, questions to the seller. You will see if he knows what he is dealing with and if he has trusted suppliers who can give him the background and details about the gemstone.

They are simple questions, like: Where does the gemstone come from? Is it treated and if so how? Can you say something about the mining conditions on site? Last but not least, ask the seller to document all relevant criteria for the gemstone in writing for you, including origin and treatment, to get a binding statement.

A glass material known as “slocum stone” can mimic the appearance of opal
A glass material known as “slocum stone” can mimic the appearance of opal
(source GIA)

Final thoughts

Only genuine gemstones have their value, today at the time of purchase and also tomorrow at a possible resale. There are unfortunately many fake gemstones on the market, fakes as synthetic gemstones or imitations. The field of different treatments of gemstones is long depending on the type of stone, there are treatments that must be marked and those that are common in the market. However, you must be knowledgeable, and your seller must educate you on this.

In general, buying on the internet is not advisable. Since you need to see the gem live, in daylight, whether you really like it. The must have confidence in the seller and ask important questions to make sure that the criteria mentioned are true. For assurance, an independent laboratory certificate is always recommended, or at least a seller who will give you the assurance through their expertise and explanations that will satisfy you.

We are specialists in fine sapphires and sustainable mining in Sri Lanka. Our philosophy is clear. We only have genuine sapphires. Any fake gemstones no matter how big and how beautiful, have a value of zero for us. Only natural gemstones have the right to be called "gemstone" in our view". For special gemstones we offer an expertise, a certificate to the sapphire to guarantee the authenticity and treatment from an independent third party.

The treatment of sapphires is quite simple, 98-99% of sapphires are heated (burned), this thermal treatment is common in the market. Any sapphire you are offered without the words "not heated" or "no heat" is heated per se, which is not a bad thing as the heat reflects an improvement in clarity and often color intensity.

Our portfolio of sapphires includes heated stones and a large portion of non-heated stones. We are experts at what we do. We know exactly where our sapphires come from, how they are treated, and we stand for our fair and sustainable mining conditions in Sri Lanka.

Genuine, natural and untreated Ceylon sapphire rough stones from CEYLONS
Genuine, natural and untreated Ceylon sapphire rough stones from CEYLONS
(Source: Ceylons)

If you are interested in genuine and natural sapphires that are of fine quality and ethically mined fairly, contact us as a producer, wholesaler and expert.

Check out our web store for fine and fair sapphires. As a wholesaler we only sell to our B2B partners, if you are a private person looking for a sapphire, contact your trusted goldsmith and tell them about us.


Which stones are real gemstones?

All natural gemstones that are not artificially made, imitated and not treated in a way that requires labeling.

How much does a gemstone examination cost?

With a gemologist or a gemstone expert, a quick examination costs between 50-100€ depending on the working time. A gemstone certificate from a gemmological lab cost between 75-150€ at smaller labs or 200-400€ at large reputable labs depending on the type of gemstone, carat weight and treatment. In case of very special rarities, an expertise can cost much more, depending on its value.

How do I determine if it is glass or a gemstone?

With a polariscope more often gem imitations like glass can be detected or with a refractometer which measures the hardness and gives a direction for the type of gemstone.

How to recognize artificial gemstone?

A synthetic diamond is confusingly like a real diamond. The difference cannot be seen with the naked eye, a microscope, or a magnifying glass: The only way to be sure that you have purchased a real diamond is to ask for a certificate of authenticity.

What is the difference between natural stone and artificial stone?

A natural stone comes from the earth and is rare because of its mineralogical properties. An artificial stone is a man-made stone from a laboratory that can be reproduced as many times as you like.

Who tests gemstones?

Gemologists and experts in gems and jewelry can examine and test gemstones. Gemological laboratories have even more professional equipment to perform even more analysis to make completely accurate statements about gemstone criteria.

How to recognize fake diamonds?

Two quick tips are: Place the diamond in a glass of water. A real diamond will sink to the bottom immediately because of density and weight. Or breathe warm breath on the diamond, a real diamond will not fog up because it distributes heat directly to the stone.

Is quartz stone an artificial stone?

Quartz stone is a man-made stone and should not be confused with quartzite in any case. Quartzite is one of the natural stones.


Dr. Peter Janowski

Dr. Peter Janowski, Co-Founder of CEYLONS MUNICH, is a visionary in the gemstone industry. With a commitment to transparency, CEYLONS offers an exquisite collection of fine and fair sapphires, accompanied by detailed origin information. Peter's & Leander’s pioneering efforts led to the establishment of ECOMINE, the world's first self-sustaining mine for Fair Sapphires.

CEYLONS | MUNICH stands for the finest Ceylon sapphires. A brand committed to responsible mining of Sri Lankan gemstones obtained in an ethical manner.

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