Authentic or Fake Opal? How to Authenticate Your Gemstone

Authentic or Fake Opal? How to Authenticate Your Gemstone

Are you in possession of a stunning opal gemstone but unsure if it is the real deal or a convincing fake? Authenticating gemstones, particularly opals, can be a tricky task for even the most experienced collectors. In this article, we will delve into the key characteristics and methods to help you determine the authenticity of your opal, ensuring that you are able to confidently showcase your genuine gemstone to the world.

Physical Characteristics of Authentic Opals

When it comes to authenticating opals, there are several key physical characteristics to look for. These characteristics can help you determine whether the opal you have is genuine or if it is a fake.


One of the most important physical characteristics of authentic opals is their color. Opals come in a wide range of colors, including white, black, blue, pink, and green. Authentic opals will typically have vibrant and vivid colors, with a play-of-color that is unique to each stone. Be wary of opals that have dull or washed-out colors, as this may be a sign of a fake gemstone.


The play-of-color is another key characteristic of authentic opals. This term refers to the way that light interacts with the gemstone, creating a rainbow-like effect of colors that seem to dance and move within the stone. Authentic opals will have a distinct and vibrant play-of-color, with flashes of red, orange, yellow, green, blue, and purple. Fake opals may lack this play-of-color or may have a static and unimpressive appearance.


Lastly, the transparency of the opal can also help authenticate the gemstone. Authentic opals will have a certain level of transparency, allowing you to see through the stone to some extent. However, opals are not completely transparent like other gemstones such as diamonds. Fake opals may be overly transparent or may have a cloudy appearance that obscures the play-of-color.

By examining the color, play-of-color, and transparency of your opal, you can better determine whether it is an authentic gemstone or a fake imitation. Remember to consult with a professional gemologist if you have any doubts about the authenticity of your opal.

Common Types of Fake Opals

When it comes to opals, it’s important to be able to differentiate between authentic gemstones and fakes. There are several common types of fake opals that you should be aware of in order to authenticate your gemstone properly.

Synthetic Opals

Synthetic opals are man-made opals that are created in a laboratory. These opals often look very similar to natural opals, making them difficult to distinguish with the naked eye. However, there are a few telltale signs that can help you identify a synthetic opal. Synthetic opals may have a more uniform color pattern, lack the characteristic play of color seen in natural opals, and may have a more perfect shape and size than natural opals.

Doublet Opals

Doublet opals are created by adhering a thin slice of natural opal to a black backing material. This creates the appearance of a thicker, more valuable opal. Doublet opals can often be identified by looking at the side of the stone – if you see a clear line where the opal is attached to the backing material, it is likely a doublet opal. Additionally, doublet opals may lack the play of color seen in natural opals.

Triplet Opals

Triplet opals are similar to doublet opals, but with an additional layer of clear material on top of the opal. This clear layer is typically made of quartz or glass, and is used to protect the fragile opal underneath. Triplet opals can be identified by the clear layer on top of the opal, as well as by the lack of depth and play of color seen in natural opals.

By being aware of these common types of fake opals, you can better authenticate your gemstone and ensure that you are purchasing an authentic opal.

Methods to Authenticate Opals

Visual Inspection

One way to authenticate an opal is through a visual inspection. Look for any irregularities in the surface of the gemstone, such as bubbles, cracks, or color inconsistencies. Authentic opals will have a smooth surface with vibrant colors that seem to dance and change with the light.

Specific Gravity Testing

Specific gravity testing is another method used to determine the authenticity of an opal. This test involves measuring the density of the gemstone by comparing its weight to the weight of an equal volume of water. Opals typically have a specific gravity between 1.9 and 2.5, so any significant deviation from this range could indicate a fake opal.

UV Light Testing

UV light testing is a popular method for authenticating opals, as many authentic opals exhibit a vibrant fluorescence under ultraviolet light. By exposing the opal to UV light, you can observe any unique patterns or colors that may confirm its authenticity. Fake opals may not display the same fluorescence or may appear dull under UV light.

By using a combination of these methods, you can effectively authenticate your opal and ensure that you are purchasing a genuine gemstone.


In conclusion, determining whether a opal is authentic or fake can be a challenging task, but by following the guidelines and tips provided in this article, you can increase your chances of authenticating your gemstone successfully. Remember to always consult with a professional gemologist if you are unsure, and to only purchase opals from reputable sources. By taking the time to authenticate your opal, you can ensure that you are getting a high-quality gemstone that will bring beauty and value to your collection.

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