Often, people might consider imitation opals as fake opals. It is made from material resembling the appearance but possesses different chemical and physical properties. These could be made from either plastic, glass, resin, and other materials. Opal-like plastic was GIA certified as imitation opal containing 80% resin and 20% silica.

However, imitation opal is different from synthetic opal. GIA states that the significant elements of synthetic opal should be silica, along with some water. It should also be composed of submicroscopic spheres and have gemological properties. Its refractive or RI index should land between 1.37 and 1.47, respectively.

Now that we have tackled what directly classifies as synthetic or man-made opal, here are four things that you need to know about them.

Polymer Impregnated vs. Lab-created

These two terms are commonly misused by amateurs who have difficulties finding the difference between imitation, synthetic, and other opal attributes. The term “polymer impregnated” refers to a synthetic opal that undergoes resin impregnation procedures. However, it may only occur if the solid stone is ready in advance.

“Lab-created” must be used to describe synthetic opals only. Marketing statements such as lab-grown opal or lab-created opal explicitly define their products as synthetic, not imitation. There have been instances wherein OLP is promoted as an impregnated opal. However, because of the plastic mixing with silica, impregnation is impossible to occur.

Market Values

Imitation and Synthetic opals have different values in the market. Synthetic opal, which is resin-free, usually has the highest value due to its chemically identical characteristics to the natural opal. Polymer impregnated synthetic opal follows at a lower price while carrying a unique vertical fire feature.


Imitation opals are categorized according to the materials used that dictates their value in the market. The values listed from the highest to lowest market value are now as follows: mineral type or resin-free synthetic opal, polymer impregnated synthetic opal, resin colloidal imitation opal, and opalescent glass.

Choosing Manufacturers

Obviously, synthetic opal has a higher market value because of better quality compared to any other man-made opal. However, this may still depend on the manufacturers who handle the different raw materials and execute quality control procedures. Faulty handling may result in low-grade products, so it is crucial to choose the right opal manufacturer.

Different Attributes and Uses

Some might ask about the exact type of opal perfect for jewelry plating. Technically speaking, all resin-free synthetic opal works well with jewelry plating. However, other products that fall under synthetic opal might not be as compatible. Still, it depends mainly on the raw materials and handling procedures by the different manufacturers.

Opals are also tested for chemical resistance, such as a thinner, methanol, and acetone. According to the three tests, Gilson Opal and Galaxy Opal, although known as resin-free synthetics, are non-chemical resistant. Whereas Bello Opal, a polymer impregnated synthetic, can resist all three of them.

Material origin and manufacturing quality play a significant role in its overall product quality, attributes, and other essential characteristics that you need to note before purchasing. It is necessary that you choose them wisely, so you do not waste money on low-quality items.

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