Shopping for a diamond or diamond ring is a big decision and often requires a lot of attention to detail. With all of the factors to consider, from style to diamond shape to budget, it’s essential to be educated on the ins and outs of diamond buying. For this reason, it is always wise to begin your journey with a trusted local jeweller who can guide you through the process.

Sometimes, however, you may have inherited a diamond or received one from friends or family. In this case, you should make sure your diamond is real. We always recommend taking your diamond to a trusted jewellery appraiser, as they have the tools and knowledge to determine if the diamond is authentic.

In the meantime, however, here are a few tips on how to test whether your diamond is real at home:


Determining if a Diamond Is Real at Home

Water Test

Here is a simple technique you can use at home to see if you have a real or fake diamond in your possession. First, fill a drinking glass with about three-quarters of water. Next, lightly place your diamond in the water and note if it floats or not. A real diamond will sink straight to the bottom due to its relatively high density, whereas a fake diamond will either stay at the top of the water or underneath the surface.


Looking for Metal Marks

If you are in possession of a diamond that is set in a ring, this may help you determine if your diamond is real or not. Real diamonds will generally be set in high-quality metals. Have a look inside the band of the ring for stamps or engravings that say 10K, 14K, 18K, or PLAT (referring to the different karats of gold or platinum. If you see these markings, it is likely that the centre stone is of value as well, and could be a real diamond rather than some other diamond simulant.


The Fog Test

This method works for both mounted and loose stones. Hold the diamond between your fingers and breathe a puff of air onto it so that a light fog appears on the diamond. As diamonds conduct heat, the fog should dissipate immediately if the stone is real. If the fog takes several seconds to go away, the diamond may be fake.


UV Light Test

This test is not necessarily 100% reliable, but it is worth mentioning. Some diamonds have fluorescence, meaning that they react to UV light. This will cause them to emit a blue glow under certain lighting conditions. If you notice that your diamond does emit such a glow, there is a decent chance it is real. However, many high-quality diamonds do not have fluorescence, so this test is only sometimes reliable.


The Dot Test

Genuine diamonds are valued for their ability to sparkle as they refract light from their many angles and internal structures. A well-cut diamond should reflect the maximum amount of light that is entering it back toward the eye, creating a pattern of dazzling sparkle. Simulated diamonds do not refract light to this level.

To test for this:

  1. Place a sheet of white paper on the table and draw a small dot.
  2. Place the stone flat side down over top.
  3. Looking through the diamond straight at the point, see if you can see the dot or its reflection.

In the case of a real diamond, the light should be dispersed in many directions, so you will not be able to look through to see a clear picture of the dot. However, fake diamonds, due to their lower light performance, may still allow the dot to remain visible.


The Sparkle Test

When holding a diamond under a normal desk light or lamp, take a look at how the light reflects off of the stone. With real diamonds, you should see bright white sparkles, often referred to as the diamond’s “fire”, whereas fake diamonds, such as Cubic Zirconia, will tend to be duller.

Sometimes, you may notice many different colours coming off of the diamond, including blue, green, red, and orange. This may be a sign that the stone is a moissanite, which is a diamond simulant rather than a diamond.


Checking the Setting and Mount

As mentioned previously, a real diamond, when mounted, is likely to be set in a high-quality metal such as gold or platinum. These rings will often have stamps or engravings on the band that indicate the metal. If you have either mounted or loose diamonds, we recommend visiting a trusted jeweller or appraiser to assess their value.


Recognizing Synthetic and Simulant Stones

Diamonds are made of pure carbon, which has unique chemical and optical refractive properties, resulting in the brilliance and appearance they have become famous for.

Aside from diamonds, there are a number of what are referred to as diamond simulants that appear similar to diamonds. These include stones such as moissanite, white sapphire, cubic zirconia, and white topaz.


Cubic Zirconia

The cheapest and lowest-quality diamond simulant, Cubic Zirconias are essentially made of glass. They can easily be spotted due to their poor sparkle. They are also very soft and tend to wear down over time.



Moissanite is an often lab-created stone similar to diamonds. These stones can be distinguished by the vast array of colours they give off when exposed to light, often referred to as the “disco ball effect.” However, as always, if you believe you are in possession of a diamond-like stone and you do not know what it is, we recommend having it looked at by a gemologist.


Lab-Grown Diamonds

Lab-grown diamonds are real diamonds that are virtually identical to natural diamonds. They have been created under conditions that mimic what takes place naturally on the earth. All diamonds should come with a grading report specifying whether they are natural or lab-grown.


White Sapphire

While often marketed as a decent alternative to diamonds, white sapphires do not exhibit the same level of sparkle and usually appear cloudy or blurry compared to diamonds. These are especially prevalent in less expensive, mass-produced jewellery purchased online.


White Topaz

This is a softer stone, which, like white sapphires, is often used as a cheaper substitute for diamonds. It can scratch relatively easily, so if you notice any scratches on white gems you are in possession of, there is a chance they are not real diamonds. Real diamonds are incredibly hard and durable and should wear well over time.


Expert Inspection Techniques

While the above tests can be done at home to give you a rough idea if your diamond is real, we always recommend taking your jewellery to a gemologist or trusted jeweller with the knowledge and equipment to inspect your jewellery and gemstones.


Inspecting the Diamond With a Loupe

Diamond professionals, gemologists, and jewellers will have their own personal loupe. This is a hand-held, 10-power magnification device which can allow them to look up closely at your diamond and jewellery. This can allow them to see any blemishes or imperfections as well as signs of whether or not your diamond is real or not.


Use a Thermal Conductivity Probe or “Diamond Tester”

Gemologists often use this tool to examine a stone’s thermal conductivity. Diamonds are conductors of heat, so a real diamond will disperse heat after it is warmed. If a stone does not disperse heat well, it is not a real diamond. This is one of the main methods gemologists may use to determine a stone’s nature.


The Bottom Line

We hope this article has given you some valuable information about diamonds and how to tell if a diamond is real. This information is often handy when you have inherited jewellery without documents or need to know its source. However, when purchasing jewellery from a trusted retailer, you should always receive authentic grading reports for the centre diamond. This grading report should also specify if a diamond is natural or lab-created and summarize its quality measurements.


Are you looking to purchase an engagement ring in Winnipeg, with a diamond, from a trusted jeweller in Winnipeg? Look no further than Omori Diamonds. We are an expert father and son team specializing in crafting fine custom jewellery, giving you access to exceptional diamonds, sapphires, and other gems. Call or inquire today to book your personalized consultation.