How To Identify A Rough, Raw & Uncut Diamond

Natural Rough, Raw & Uncut Diamonds

Diamonds form naturally deep beneath the Earth's surface, but they can also be made in a laboratory by diamond manufacturers. Learn about the interesting facts about this highly sought after gemstone and how to identify them.

You may have asked yourself more than once, "What makes diamonds so special and rare? Why do people make such a big fuss about a little rock?" Diamonds are in a class all by themselves for good reason. The reality is no diamond is born looking pretty. A lot of work goes into the making of a diamond as we know it. Diamond deposits dwell deep below the earth and are brought up through volcanic eruptions. They are like every other crop waiting for the harvest moon. But unlike other crops, diamonds wait millions and even billions of years before they reach maturity. There's a lot about diamonds that most people don't readily know. Here's a quick rundown of the most basic yet astounding facts you need to know about diamonds:

Identifying Natural Rough, Raw & Uncut Diamonds

Natural Rough, Raw & Uncut Diamonds

Natural Rough, Raw & Uncut Diamonds

Natural Rough, Raw & Uncut Diamonds

Natural Rough, Raw & Uncut Diamonds

Natural Rough, Raw & Uncut Diamonds

Natural Rough, Raw & Uncut Diamonds

Natural Rough, Raw & Uncut Diamonds

Natural Rough, Raw & Uncut Diamonds

Select Diamonds

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Identifying Natural Rough, Raw & Uncut Diamonds.

Due to their incredible durability and sparkling beauty, diamonds are one of the most sought after gemstones in the world. While it's easy to recognize a cut diamond, however, not many people would be able to tell whether an uncut, rough or raw diamond is the real thing or not.

Uncut rough diamonds look very similar to water-worn quartz pebbles. However, there are other rocks that can be mistaken for raw diamonds by people who do not know how to spot the precious material. Luckily for people who want to learn how to identify a raw diamond, there are various ways to identify a raw diamond with a high degree of certainty.

If you think you have a rough diamond or think you have found a diamond. This guide will tell you how, and how not to identify rough diamonds as they are found in nature.

The chances of finding a rough diamond are extremely rare. Odds are you did not find a diamond. First a few questions:

  1. Is the suspected diamonds larger than 8 mm (3/8 of an inch)?

  2. Does the suspect diamond weigh more than 2 grams (10.00 carats)?

  3. Did you find more than one suspected diamond?

If the answer to any of the above questions is YES, then you probably don't have a diamond or did not find a diamond.

Only one in a million diamonds are gem quality 1.00 carat stones; one in five million are gem quality 2.00 carat stones; and one in 15 million are gem quality 3.00 caraters. You may have a better chance of striking gold (or diamonds) by playing the lottery! Diamonds over 8 mm, in excess of 2 grams in weight are extremely rare. The chances of finding a diamond over 8 mm, in excess of 2 grams in weight are 1 in 1,000,000,000. That is one chance in a billion!

Ok, so you think you beat the odds and actually found a rough diamond. Now how do you test it to confirm it is a diamond? It's best to do a few simple DIY tests before taking the pieces to a gemologist to look at:

How To Tell If A Diamond Is Real

Test Diamonds At Home

How To Tell If A Diamond Is Real

Testing Natural Cut And Polished Diamonds

Testing natural cut and polished diamonds.

How To Tell If A Diamond Is Real

Testing Natural Rough, Raw And Uncut Diamonds

Testing natural rough, raw and uncut diamonds.

1. Look At The Diamond Through A Loupe

A loupe is a special magnifying glass, that you can buy at any jewellery shop, used for diamonds, gemstones and jewellery. When using a loupe, look for blemishes and imperfections within the diamond. While a fake diamond can be perfectly constructed, a diamond will have small imperfections called inclusions.

2. Crystal Form

Looking at the crystal form is a quick way of differentiating diamond from most of the other minerals that look like diamond.

Crystal Form

Crystal form.

Diamonds are cubic (isometric) form. The most common mineral that looks like a diamond is quartz and it is hexagonal form. When looking down on the crystals from the top, with the point of the crystal aimed at your eye, quartz will have six sides and a diamond will have four sides. If you see six sides than you probably found quartz.

3. Fracture

When diamonds break, they will cleave creating smooth, flat surfaces. Quartz and glass will create conchoidal surfaces when they break.



If you see curved conchoidal surfaces (see photo above) then you know your sample is not a diamond.

4. Test Hardness

You can not test the suspect diamond by scratching glass.

Many minerals scratch glass. Glass is 5.5 on the Moh's Scale of Hardness. The following list is of common minerals that scratch glass, may look like diamonds and they are much more common than diamonds:

Albite Grossular Quartz
Beryllonite Marialite Sanidine
Boracite Oligoclase Sillimanite
Corundum Orthoclase Spodumene
Danburite Petalite Topaz
Elbaite Phenakite Zircon
Euclase Pollucite Zoisite

Test hardeness.

So do not try scratching glass with the suspected diamond. The only hardness test that will identify a diamond is scratching corundum. Corundum, which includes all rubys and sapphires, is 9 on the hardiness scale. If your suspected diamond crystal can scratch corundum, then there is a good chance that you found a diamond. But no other hardness test will identify a diamond.

While a diamond is formed with very strong materials, fakes like cubic zirconia and moissanite are quite durable and scratch-resistant as well. For these reasons, the scratch test is not accurate. You are better served to use other tests such as a thermal conductivity test or having the diamond inspected with a professional loupe tool.

5. Test For Thermal Absorption

Diamonds absorb heat better than any other mineral and there are a wide variety of portable diamond testers on the market.

Test for Thermal Absorption

Test for thermal absorption.

These diamond testers are hand-held devices with a metal probe that is held in contact with the suspected diamond. It generates a small amount of heat and measures the speed that the heat is absorbed by the crystal. Good testers can differentiate between diamond, moissanite (a common synthetic diamond-simulant), and other minerals.

You do not have to buy a diamond tester. Almost any reputable jeweller will own one, and testing is quick and easy. So try visiting your local jeweller and ask if he will test your suspected diamond.

6. Specific Gravity

Those who want to know how to identify a raw diamond would be remiss not to learn about specific gravity. Simply put, specific gravity is the ratio that exists between the density of a gemstone and a reference liquid. Typically, this liquid is pure, distilled water, a liquid that has a density of 1 g/mL.

Diamonds have a specific gravity of 3.5 to 3.53. In comparison, quartz has a specific gravity of 2.6 to 2.7. By learning what the specific gravity of a gemstone is, it is possible to know with certainty whether it is a raw diamond. This property of diamonds also serves as a way to separate them from other gemstones using shaker tables or similarly purposed tools.

Use this simple test to ensure a diamond is real: Find a normal sized drinking glass and fill it 3/4 of the way with water. Carefully drop the loose stone into the glass. If the gemstone sinks, it's a real diamond. If it floats underneath or at the surface of the water, you have a fake on your hands. A real diamond has high density, so the water test shows if your stone matches this level of density.

7. Fog Test

For the fog test, hold the diamond or ring between two fingers and breath on it with a puff of air. A light fog will form on the diamond because of the moisture and heat in your breath.

If the fog dissipates right away, the diamond is real. If it takes several seconds for the fog to disperse, it is likely a fake diamond. Diamonds effectively conduct heat and therefore disperse heat quickly.

8. Check Setting & Mount

If a diamond is already placed in a ring, look at the type of setting and mount that's used.

Because of a diamond's large price tag, a real one will only be set in high quality jewellery. For example, a real diamond will be set in materials such as white gold, platinum, yellow gold, pave or side-stone setting and halo setting rings.

To see if the setting is truly as described, look inside the ring's center for markings. As an example, the notes 10K, 14K, and 18K indicate the type of gold used. The markings PT and Plat refer to platinum. If you see a number such as 585, 770, 900, and 950, those are markings indicate platinum or gold as well.

If you see a "C.Z." stamp or engraving, the gemstone is a cubic zirconia, and not a real diamond.

9. Heat The Stone & See If It Shatters

Diamonds are made of incredibly strong material and will be unresponsive to high heat.

To test this, grab a drinking glass and fill it with cold water. Use a set of plyers or fireproof gloves to hold the stone. Heat the stone with a lighter for approximately 40 seconds, then drop the stone directly into the cold water.

If the stone shatters, it is made of weaker components and is not a real diamond. A true diamond will show no reaction.

This method tests the quality and strength of the stone. Because of the quick expansion and contraction of heat, weak materials like glass or cubic zirconium will crack and break. Think of a glass or Pyrex dish you use for cooking. If you pull the dish out of a hot oven and try to wash it immediately, the shock in temperature change may shatter the dish.

Because diamonds are one of the strongest materials on the planet, it will be resistant to such heat tests. Heat will disperse quickly and the diamond won't be affected by the change in temperature.

10. UV Light Test

To test a diamond in a different way, place it under a UV light and watch the reaction. Most diamonds will emit a blue colored glow, but not all of them. Some diamonds do not glow under UV light. For this reason, if the stone does not glow, the results don't necessarily indicate that it's a fake diamond.

Because this test is not definitive, it's best to have a diamond expert or jeweller use their advanced equipment to test the stone.

11. Hold It In The Light To See How It Sparkles

The way that diamonds reflect light is unique: Inside the stone, the diamond will sparkle gray and white (known as "brilliance") while outside of the gem, it will reflect rainbow colors onto other surfaces (this dispersed light is known as "fire").

Reflectivity encompasses both the brilliance (white light sparkle) and fire (colored light) that shines off of a diamond's table.

A fake diamond will have rainbow colors that you can see inside the diamond.

People have a misconception that diamonds sparkle like a rainbow, but they don't. They do sparkle, but it's more of a gray color. If you see something with rainbow colors [inside the stone], it could be a sign that it's not a diamond.

To test for reflectivity, use the sparkle test:

Sparkle Test

12. Look At The Stone's Refractivity

When you see a diamond sparkle, you're experiencing its ability to bend and refract light. When light strikes the pavilions (the angled surfaces on the lower half of the diamond), it is bounced and refracted up through the diamond's table (the top, flat surface) to the naked eye. When a diamond does this well and sparkles radiantly, it is called Scintillation.

Diamonds are so sparkly because of the way they refract and bend light. Glass, quartz, and cubic zirconium may mimic a diamond's brilliance, but they have much lower refractive indexes. Stones that are not diamonds, will not refract light as well. They will have less brilliance, if any at all.

This means that if your stone isn't in a setting, you can place it over a newspaper and the light will scatter inside the real diamond and prevent a black reflection. A fake diamond will let the black shine through, and you may even be able to read a word depending on the size of the fake stone.

If your diamond is mounted, make sure you can't see through it to the mount itself - that's a very bad sign.

To test a diamond's refractivity, use the following tests:

'Read-Through' Effect

The Dot Test

13. Testing A Real Diamond With High Profile Weighing

Jewellers and gemologists usually have a very fine tuned scale for measuring small differences in weight. The weight of a real diamond will be lower than fake stones like the cubic zirconia, but only special scales for weighing carats will be able to detect these minute differences.

This one will only work if you have access to a cubic zirconia, a substance often used to replace real diamonds, of a similar size. Interestingly enough, a diamond weighs less than a cubic zirconia. If your stone weighs 55% less then what the cubic zirconia weighs, yours is a real diamond. If it weighs the same, it may very well be a fake.

14. Spot A Fake Diamond Using Electricity Conductivity

Detecting a fake diamond can also be achieved through a electricity conductivity test performed by a jeweller or gemologist. Diamonds conduct electricity better than other stones, including the difficult synthetic moissanite.

An electricity tester will provide a clear sign as to whether or not the stone is real or created by a lab. A diamond will show conductivity while other stones like moissanite and cubic zirconia will not.

15. Do Diamonds Show Up On X-Ray?

While a cubic zirconium can go unnoticed in an X-ray, a real diamond cannot. If you have it X-rayed and the stone does not appear, it is not authentic.

16. Microscope Test

Often, people who want to know how to identify a raw diamond are glad to find out it is possible to do this just by looking at the stone. However, it is also necessary to use a 10x power jeweller's loupe or, even better, a microscope.

With a 1200x magnification on a power microscope, a jeweller or gemologist is able to scrutinize the stone in detail. At this level of magnification, they'll be able to see inclusions and small differences in real diamonds compared to moissanite. There are two main things to look for when trying to identify a diamond. The first is its appearance; under the microscope, diamonds look as if they had been coated with a thin film of Vaseline. The second thing to look for is certain markings such as indented triangles, parallelograms or rotated squares.

How To Spot Or Tell If Other Stones Are Real Or Fake Diamonds

With the rising popularity in other gemstones, here are some steps to spotting a stone that to the naked eye may appear similar to a real diamond.

How To Recognize Synthetic Diamonds

With an increasing prevalence of synthetic diamonds, it's important to know how to tell the difference between lab-created diamonds and natural diamonds. Synthetic diamonds have similar chemical and molecular components to real, natural diamonds.

Because of their intricate internal qualities, we recommend having the diamond reviewed by an expert. They can run the conductivity test and look at the stone under high magnification. Even when it's unclear to the naked eye how a synthetic diamond differs from a natural diamond, it is crucial for resale and insurance values.

How To Recognize Cubic Zirconia

A cubic zirconia is one of the easier fake diamonds to test for authenticity. By using the sparkle test, for example, it's relatively easily gauge the amount of sparkle and fire a stone is giving off.

In addition, cubic zirconias reflect orange tinted light. They also weigh more than a real diamond and generally don't have imperfections or inclusions. Real diamonds will have inclusions that can be seen by the naked eye or under a diamond expert's microscope.

How To Recognize White Sapphire

Sapphires are commonly available in blue and a wide range of colors including white, which looks clear to the naked eye. White sapphires are often posed as diamonds but don't offer the diamond's signature sparkle and contrast of dark and light areas.

If the stone seems more blurred in coloring, meaning it doesn't have distinct light and dark parts, it is likely to be a white sapphire.

How To Recognize Moissanite

Perhaps the best actor in the fake diamond world is the synthetic moissanite. Distinction between the two is usually difficult for the naked eye and requires the expertise of a diamond professional.

An electricity conductivity test will indicate if the gemstone is a moissanite or a true diamond. Note that the thermal conductivity test is not a valid technique for recognizing moissanite because they have nearly identical thermal conductivity as diamonds.

How To Recognize White Topaz

While a white topaz may look like a diamond at first glance, several characteristics separate it from a real diamond.

The exterior is softer than a diamond and is easily scratched by other materials. You can also look closely at a white topaz using magnification to see if there are any scratches on the surface. Diamonds will not have scratches because of their durable composition.

Final Thoughts

The odds are against you finding a diamond. But if you are not convinced, many of the tests in this guide, like the fog test and the thermal conductivity test, can help determine if a diamond is real. If it passes all of the above and even if you found a real diamond and purchased a diamond tester to verify, nobody will take you seriously. To get the most definitive answer, you should take it in to a professional jeweller.

The ONLY way you will convince anybody it is a real diamond is to have it certified by the Gemmological Institute of America (GIA). For a fee they will test your "diamond" and give you a certificate absolutely, positively identifying it as diamond, plus they will give you back the diamond unharmed. With that certificate you will have proof of your find, and buyers will be seriously interested in purchasing your find.

Because a GIA certificate will eventually be required anyway, save your money and do not buy a diamond tester. Instead send it straight to the GIA for a certification.