How to Tell if a Diamond is Raw: 7 Expert Tips

Diamonds are arguably the most valuable precious stones globally, and it has been so for a while. The high costs of diamonds result from the costs incurred at every step of the industry’s value chain– from mine to the finger. Therefore, it is good to know how to identify a raw diamond from fakes and lookalikes if you plan to have anything to do with them.

How to Identify Raw Diamonds

Identify raw diamonds
Raw Diamond
Image Credit: Dkas Mineral Limited

You can identify fakes and lookalikes of raw diamonds in several ways; some methods can be done quickly at home, while others require specialized equipment.

Some of these methods might be inconclusive on their own, and it would be best if you ran multiple tests to get a more accurate answer. Also, some of the stones might share a couple of similarities with a raw diamond and can lead you to become confused if you are not an expert jeweler.

1. Finding out its source

Large and reputable jewelry designers usually disclose the story behind each stone, detailing where and how it was mined and processed. Find out the stone’s origin if you have access to such information.

Miners mostly find raw diamonds near igneous stones known as kimberlite pipes; if the source of your stone is from a kimberlite pipe, it’s likely a diamond. However, not all diamonds come from kimberlite pipes; you can find some in the ocean or cratons in the ground.

2. Measure The Density Of The Stone

You can know if what you have is a raw diamond by measuring the density of the stone. The density of a raw diamond is 3.5–3.53 g/cm3, and anything less than or above that is not a diamond. However, it’s important to note that other stones have a similar density as diamonds.

To check the density of a diamond, you would need the following materials:

  • A water container that has measurement in milliliters
  • A scale that weighs in grams; the most reliable are electric scales.

When you have these materials, you should follow the steps below:

Step 1– Weigh the stone on your scale.
Step 2– Take note of the quantity of water in your container.
Step 3– Place the stone into the water container; do this carefully to avoid any spillage of the water. Once the water settles, note the new quantity in milliliters.
Step 4– Subtract the quantity before from the after measurement. 
Step 5– Divide the weight of the stone by the result you got above; the result you get is the density of the material.

In simple terms, the formula for density is = Stone weight / (Quantity of water after – Quantity of water before). If the result you get is within the density range, the stone you have is likely a diamond.

3. The Scratch Test

Diamonds are very hard materials; they are the hardest known material on earth and score a perfect 10 on the Mohs Hardness Scale.

The hardness of diamond means that it is almost impossible for you to scratch a raw diamond with any other material. The hardness of diamonds means you can use them to cut and scratch many other materials that would’ve been difficult to do.

To test if the stone you have is a diamond, try to use any other hard substance to scratch it. Most metals fall at 5 or under on the Mohs Hardness Scale, meaning that if you use them to scratch the stone, there’ll be no effect if it’s a diamond.

However, be careful not to use a crystal such as corundum when trying the scratch test; the stone has a hardness rating of 9, and you would see scratches on your stone even if it’s a diamond.

4. Refraction Test

The sparkle effect that diamonds have is a result of how they refract or bend light. Other diamond imitations like glass and cubic zirconia bend relatively less light because of their lower refractive indexes. Diamond’s high refraction means that when you put it on top of a text, you won’t be able to make out what you’re reading.

You can conduct the refraction test by placing your stone over a written text, like a newspaper, to see if you can read the paper through the stone. Also, when the diamond is set upon a ring, you should not be able to see the setting through the stone; other stones tend to be more transparent.

5. Flame Test

Natural diamonds form over 1 – 3.5 billion years, 93 miles beneath the earth; therefore, nature formed these stones in harsh conditions. Diamond gemstones form under temperatures above 1000°C (1832°F) and extreme pressures. When processed, however, a natural diamond can withstand heat of up to 763° Celsius (1405° Fahrenheit) before turning to vapor.

To test if the stone you have is a diamond, put it into a stove or candle fire for about 20 seconds; you will notice the stone quickly becomes black. Rapidly cool the stone in a glass of water, wipe it with alcohol, and it should be good as new. In most cases, the rapid temperature change would affect the structure of a diamond lookalike.

6. Conductivity Test

Most natural diamonds insulate electric current, differentiating them from diamond lookalikes such as moissanite. If you test the conductivity of your stone and you find out that an electric current passes through it, it’s probably not a diamond.

To perform the conductivity test on your stone, you need to get a conductivity meter. Conductivity meters are small handheld devices that can check thermal and electric conductivity. 

To use your meter, switch it on, place its pointed end on the stone, and press the test button. Depending on the type of meter you buy, a light would be displayed indicating if your stone conducts electricity or not.

7. Professional evaluation

Even with all the DIY methods of checking the authenticity of your diamond, it’s still most advisable that you take it to a professional jeweler. They are better positioned not to make mistakes since they have more experience and better equipment than you.

Some jewelers do not check the stones themselves; instead, they send them to the Gemological Institute of America (GIA) for proper assessment. The advantage of a thorough GIA verification is that they check the stone’s authenticity and grade it based on other factors.

The proper evaluation lets you know if your stone is a raw diamond and informs you of the value of the diamond you have at hand in case you want to sell it.

Do Other Stones Look Like Diamonds?

While diamonds have a unique glittery appearance, other stones look like them with naked eyes and can be easily mistaken for raw diamonds to the unsuspecting. Examples of stones that can be mistaken for raw diamonds are:

  • Glass
  • Moissanite
  • Synthetic Cubic Zirconia
  • Quartz
  • White Sapphire
  • White Topaz

Can Real Diamonds Break?

Even though diamonds are the hardest minerals on earth, this doesn’t mean they cannot break. Many people confuse the hardness of diamonds to mean they’re unbreakable when it refers to the resistance of the stone to scratching. Instead, an object’s tenacity measures its resistance to blows, and the tenacity of a diamond is considered brittle, and a strong blow with a metal hammer can break it.

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