Turquoise is a beautiful and valuable gemstone that has been used for centuries in jewelry making and other decorative applications. However, determining whether turquoise is stabilized or natural can be a challenging task for both experienced and novice gemologists. In this article, we will explore the various characteristics of stabilized and natural turquoise and provide tips on how to determine the authenticity of your turquoise.
What is Stabilized Turquoise?
Stabilized turquoise is a type of turquoise that has been treated with a stabilizing agent to improve its hardness, durability, and color. This process typically involves impregnating the porous material with a clear epoxy resin or similar substance that hardens and protects the stone. The stabilizer can also help prevent the turquoise from changing color due to exposure to light, heat, or chemicals.
While the stabilization process can enhance the beauty and longevity of the turquoise, it can also affect its value. Stabilized turquoise is generally considered less valuable than natural turquoise because it has been altered from its original state.
How to Identify Stabilized Turquoise
One of the most reliable ways to identify stabilized turquoise is to examine its surface texture. Stabilized turquoise tends to have a smoother and shinier surface compared to natural turquoise. This is because the stabilizing agent fills in the pores and imperfections of the stone, creating a uniform surface. In contrast, natural turquoise often has a more textured or pitted surface due to the presence of natural inclusions and veins.
Another characteristic of stabilized turquoise is its uniform coloration. Stabilization can give turquoise a brighter, more vibrant color that is consistent throughout the stone. If the turquoise appears too perfect or artificially bright, it may be an indication that it is stabilized.
Additionally, stabilized turquoise may exhibit signs of internal fractures or cracks that have been filled with the stabilizing agent. These fractures can sometimes be visible under magnification or when the stone is held up to the light.
Finally, stabilized turquoise is generally more resistant to scratches and abrasions compared to natural turquoise. You can perform a scratch test on a small area of the stone using a sharp object such as a knife or needle. If the turquoise is easily scratched or dented, it is likely natural.
What is Natural Turquoise?
Natural turquoise is a gemstone that forms when copper-rich groundwater percolates through porous rock and reacts with minerals such as aluminum, phosphorus, and iron. This process can take millions of years and results in the formation of turquoise veins and nodules within the host rock.
Due to its rarity and unique coloration, natural turquoise is considered more valuable than stabilized turquoise. However, natural turquoise is also more fragile and susceptible to damage, which can make it challenging to work with.
How to Identify Natural Turquoise
One of the most apparent characteristics of natural turquoise is its surface texture. Unlike stabilized turquoise, natural turquoise often has a rough, bumpy surface with visible pits and imperfections. These surface features are a result of the stone’s natural formation process and cannot be replicated through stabilization.
Another way to identify natural turquoise is by examining its color and pattern. Natural turquoise tends to have a more mottled appearance, with variations in color and tone throughout the stone. This is because the stone forms in irregular patterns and may contain different minerals and impurities in various areas.
You can also look for signs of aging and wear on the surface of the stone. Natural turquoise can develop a patina over time, which is a thin film that forms on the surface due to exposure to air and oils from the skin. This patina can give the turquoise a softer, more muted appearance compared to newly mined stones.
Finally, you can perform a specific gravity test to determine if your turquoise is natural or stabilized. Specific gravity is a measure of the density of the stone and can help differentiate between natural and stabilized turquoise. To perform this test, you will need a precision scale that can measure up to 0.01 grams and a container of water. Weigh the turquoise in air and record the weight, then weigh it again while submerged in water. Divide the weight in air by the weight in water to get the specific gravity. Natural turquoise typically has a specific gravity between 2.6 and 2.9, while stabilized turquoise has a higher specific gravity due to the presence of the stabilizing agent.
Conclusion
Determining whether your turquoise is stabilized or natural can be a challenge, but by examining the surface texture, coloration, and internal structure of the stone, you can make an informed decision. Remember that stabilized turquoise tends to have a smoother surface, uniform coloration, and a higher resistance to scratches and abrasions. In contrast, natural turquoise often has a rougher surface with visible imperfections and variations in color and tone. While stabilized turquoise may be more durable and vibrant, natural turquoise is generally considered more valuable due to its rarity and unique beauty.
