Have you ever been captivated by the mesmerizing dance of color within an opal, only to wonder if its beauty is genuine? The allure of opals lies in their unique play-of-color, a phenomenon that imitations often struggle to replicate. But with the market flooded with synthetics and simulants, distinguishing a real opal from a fake can be tricky. Investing in what you believe to be a precious gemstone, only to discover its artificial origins, is a disappointing experience. It's important to learn the key characteristics of natural opals so you can confidently choose a piece that is truly authentic and valuable.
Knowing how to identify a real opal not only protects your investment but also allows you to appreciate the gem's natural beauty and rarity. Natural opals are formed over millions of years through a complex geological process, making each one a unique work of art. Understanding the differences between natural and synthetic opals, or even common imitations, will empower you to make informed purchasing decisions and appreciate the true value of these magnificent gemstones.
How can I tell if an opal is real?
Does real opal always show fire from every angle?
No, real opal does not always show fire (play-of-color) from every angle. The visibility and intensity of the fire depend on the opal's internal structure, the angle of light hitting it, and the viewing angle. Some angles might show vibrant colors, while others might appear more subdued or even lack visible fire.
While all precious opal will exhibit *some* play-of-color, the degree to which it is visible can vary significantly. The arrangement of silica spheres within the opal dictates how light is diffracted and scattered, creating the spectral colors we see. If the light source or the viewer's position isn't aligned favorably with these structures, the fire might be minimal or absent. Furthermore, different types of opal will exhibit different play-of-color characteristics. For example, crystal opals can appear almost clear until tilted, revealing their vibrant fire, while bolder patterns are more visible from a wider range of angles. Other factors like body tone (the background color of the opal) can also influence the perception of fire. A darker body tone can enhance the visibility and contrast of the fire, making it seem more intense even if the actual play-of-color isn't drastically different from an opal with a lighter body tone. Therefore, it's important to assess an opal's fire by examining it under different lighting conditions and from various angles to get a complete understanding of its play-of-color. Remember that opacity can also affect how light travels through the stone.What tests can I do at home to check if an opal is genuine?
While no at-home test is 100% definitive, you can perform several simple checks to help determine if an opal is likely real. These include visual inspection for imperfections (in natural opals), examining for a consistent pattern (which indicates synthetics), and a simple scratch test on a less visible area. Keep in mind that these tests are only indicative and professional gemological testing is always recommended for conclusive verification.
Visual inspection is a key first step. Natural opals often have imperfections, matrix (host rock), or slight irregularities in their play of color. Perfectly uniform patterns, especially in low-priced opals, are a red flag for synthetics or doublets/triplets (opal composites). Look closely with a jeweler's loupe if you have one. A doublet or triplet will often have a distinct, flat line where the layers are glued together, visible from the side. Also examine the back of the stone; a blackened back is common in doublets and triplets, concealing the artificial base. The scratch test involves gently trying to scratch the opal with a piece of glass or quartz. Opal has a hardness of around 5.5-6.5 on the Mohs scale. If the opal is easily scratched by glass (typically around 5.5), it's likely a simulant made of a softer material. However, proceed with extreme caution as you could damage a genuine opal. This test should only be done as a last resort and on an inconspicuous area. If you're dealing with a doublet or triplet, scratching the surface layer could easily reveal the underlying material. Remember that some opal simulants like Slocum stone are actually quite hard and may pass this test, making it an unreliable standalone method. Finally, consider the price. Gem-quality opals, particularly those with strong play of color, are valuable. If a stone advertised as an opal seems too good to be true for the price, it likely is. While online marketplaces can offer some good deals, extremely low prices are a common indicator of synthetics, simulants, or doublets/triplets masquerading as solid opals. When in doubt, seek the opinion of a qualified gemologist for a professional assessment.Are there specific inclusions that indicate a fake opal?
Yes, certain inclusions are strong indicators that an opal is synthetic or imitation. These inclusions typically point to the manufacturing process rather than natural formation within the earth.
While natural opals often contain inclusions (like sand, potch lines, or even fossils), the type and pattern of inclusions in fake opals are often giveaway signs. For example, "pillar" or "lizard skin" patterns are common in synthetic opals, caused by the way the silica spheres settle during the creation process. Additionally, excessive uniformity or perfect layering of color play is rarely seen in natural opals; if the pattern is *too* good to be true, it probably is. A "honeycomb" structure is also indicative of a synthetic opal, specifically those created using the Gilson method. Another common sign is the presence of plastic or glue-like substances as inclusions. Natural opals are primarily composed of hydrated silica and should not contain these materials. Furthermore, be wary of opals with a consistent, repeating pattern of color play that looks artificially manufactured, as this is not characteristic of natural opals which display a more random and organic distribution of color. Examination with a loupe or microscope can often reveal these telltale signs.How does the price of an opal relate to its likelihood of being real?
The price of an opal is a strong indicator of its authenticity; generally, if an opal is significantly cheaper than comparable opals in the market, it's likely to be a synthetic, imitation, or a heavily treated natural opal. Genuine, high-quality opals with vibrant play-of-color, substantial size, and good clarity command a premium price reflecting their rarity and desirability.
Opals are valued based on several factors, including the type of opal (e.g., black, white, crystal, boulder), the intensity and pattern of the play-of-color, the body tone, the size, the clarity (presence of inclusions), and the cut and polish. Synthetics and imitations often mimic some of these characteristics, but rarely can they replicate the complexity and natural beauty of a genuine opal at a comparable cost. For example, a synthetic opal might have a vibrant color, but it may exhibit a "columnar" or "snake skin" pattern under magnification, a telltale sign of its artificial origin. Similarly, heavily treated opals, such as those that have been dyed or stabilized with polymers, might appear attractive initially but will not hold their value over time and may even degrade.
Therefore, it's crucial to research the market value of opals based on their characteristics before making a purchase. A suspiciously low price should raise red flags and prompt further investigation, such as requesting a certificate of authenticity from a reputable gemological laboratory or consulting with an experienced opal dealer. While bargains exist, particularly at gem shows or directly from miners, extreme discounts are usually indicative of a problem.
What is the difference between a doublet/triplet and a solid opal?
The key difference lies in their composition: a solid opal is a single, naturally occurring piece of opal, while a doublet is composed of two layers (a thin slice of opal glued to a dark backing, typically ironstone or potch), and a triplet consists of three layers (a thin opal slice sandwiched between a dark backing and a clear quartz or glass dome).
Doublets and triplets are created to enhance the appearance of thin or less vibrant opal by providing a dark background that intensifies the play of color and a protective, magnifying top layer. Solid opals, on the other hand, showcase the opal's natural beauty in its entirety. Because they're made of a single piece of opal they are generally more valuable, especially if they display high-quality color play. Detecting the difference often involves careful examination. Look at the side of the stone: distinct layers are a telltale sign of a doublet or triplet. Doublets and triplets may also appear unnaturally flat or have a "plastic-y" appearance due to the clear top layer. A solid opal will have a consistent composition throughout, without visible layering when viewed from the side. However, be aware that well-made doublets and triplets can be quite convincing and require a trained eye or professional evaluation to identify definitively.Can a jeweler definitively tell me if an opal is real?
Yes, a qualified and experienced jeweler specializing in opals can almost always definitively tell you if an opal is real. They possess the knowledge, tools, and experience to differentiate between natural opals, synthetic opals, and imitations.
A jeweler's assessment often involves a multi-faceted approach. They'll begin with visual inspection, looking at the opal's play-of-color, its body tone (background color), and any inclusions or imperfections. Natural opals often possess a more chaotic and less structured play-of-color compared to the regular patterns seen in many synthetic opals. They will also examine the body of the opal for signs of a doublet or triplet, which are composite stones made with thin slices of opal glued to a base or under a clear top layer. These are real opals, but not solid natural opals.
Beyond visual inspection, jewelers may use magnification (a jeweler's loupe or microscope) to examine the opal's surface and internal structure more closely. This can reveal telltale signs of synthetic creation, such as a "snake skin" or "lizard skin" pattern commonly found in Gilson opals. Refractometers can be used to measure the refractive index, a physical property that differs slightly between natural and synthetic opals. In some cases, a jeweler may even use ultraviolet (UV) light to examine the opal's fluorescence, as certain synthetic opals exhibit a distinctive glow. If there is any doubt, advanced testing like X-ray diffraction can be used.
What should I look for under magnification to spot a fake opal?
Under magnification (10x or higher), look for signs of artificial construction. Specifically, examine the play-of-color patterns: are they unnaturally regular or blocky? Are there telltale "snake skin" or "lizard skin" patterns, often indicative of polymer impregnation or plastic opals? Check for a dot-matrix pattern (like pixels), which signals a Gilson opal or other synthetic. Also scrutinize the surface for a plastic-like sheen or a layered appearance. Finally, look for glue lines or areas where different materials have been bonded together, suggesting a doublet or triplet construction being passed off as a solid opal.
While natural opals exhibit a chaotic and organic arrangement of color play, synthetics often display repeating patterns. The Gilson opal, a common synthetic, is famous for its "snake skin" or "lizard skin" appearance under magnification, arising from the way the silica spheres are structured during manufacture. This texture is almost never found in natural opals. Another giveaway is a dot-matrix pattern, resembling tiny pixels, which is particularly evident in some lower-quality synthetics or those attempting to mimic particular opal types. Beyond the play-of-color, the background material, known as the "potch" in natural opals, can offer clues. In natural stones, the potch will often have a granular or somewhat rough texture. In contrast, the base material of a synthetic opal may appear too uniform, plastic-like, or glassy. Also, examine the stone's edges. Doublets and triplets, designed to mimic solid opals, are constructed by layering thin slices of opal with other materials (often a dark backing of obsidian or a clear quartz cap). Under magnification, you may see the glue lines where these layers are joined, or the different refractive properties of the materials used.So, there you have it! Armed with these tips, you're well on your way to spotting a genuine opal. Don't be afraid to get up close and personal with those beauties and trust your gut. Thanks for reading, and feel free to swing by again for more sparkly insights!