Moonstone is a popular gemstone, prized for its unique, ethereal glow that seems to shift and dance within the stone. Its captivating appearance, often reminiscent of moonlight, makes it a sought-after gem in various forms of jewelry. However, this popularity means the market contains numerous imitations and look-alikes. Knowing how to identify a genuine moonstone is crucial for buyers.
Identifying Moonstone’s Unique Optical Effects
Genuine moonstone is recognized by adularescence, a soft, billowy, blue-to-white light that appears to float just beneath its surface. Often described as resembling moonlight, this optical effect is caused by light scattering within the stone’s layered feldspar minerals structure. As the stone is tilted, this luminous sheen should move across its surface, creating a dynamic, fluid appearance.
Some moonstones, particularly Rainbow Moonstone, exhibit a broader spectrum of iridescent colors, known as schiller or labradorescence. While distinct from classic adularescence, this vibrant play of color results from similar internal structures. The color play can range from white and blue to peach or gray, with the quality and intensity of this “flash” serving as a primary indicator of authenticity and value.
Examining Physical Characteristics and Inclusions
Beyond its characteristic light play, genuine moonstone exhibits specific physical traits. Natural moonstone can vary in clarity, ranging from transparent to translucent, with highly transparent stones displaying strong adularescence. The stone has a relative softness, registering between 6 and 6.5 on the Mohs scale, making it susceptible to scratches. Therefore, a scratch test is not recommended.
Natural moonstone often contains unique internal features that serve as hallmarks of its natural origin. These can include fine, parallel stress cracks, sometimes referred to as “centipede-like” inclusions, or tiny mineral inclusions. These internal characteristics indicate a natural origin, whereas synthetic stones typically appear flawless and uniform. Additionally, genuine moonstone often feels noticeably cool to the touch due to its mineral composition, a tactile difference compared to glass or plastic imitations.
Distinguishing from Common Imitations
Several materials imitate moonstone. Glass imitations, often marketed as “Opalite” or “moonstone glass,” typically display a uniform, milky, or bubbly appearance without the true, floating adularescence of natural moonstone. Any “flash” in glass imitations is usually superficial and does not move with depth as the stone is tilted. These glass fakes may also feel warmer to the touch compared to genuine moonstone.
Some synthetic stones, such as synthetic spinel, or other natural stones like labradorite, can mimic the general appearance but lack the specific internal structure or nuanced, floating adularescence of natural moonstone. While Rainbow Moonstone is a type of labradorite, other forms of labradorite may be misrepresented as moonstone without its characteristic adularescence. Chalcedony or quartz can also be dyed or treated to superficially resemble moonstone, but they will not exhibit the specific optical effect that defines genuine moonstone.
Practical Tips for Evaluation
When evaluating moonstone, examine it under various light sources. Observe it in natural light and different artificial lights to reveal the full extent and quality of its adularescence, which should move as the stone is tilted from multiple angles. A jeweler’s loupe or magnifying glass can assist in identifying internal inclusions or signs of artificiality not visible to the naked eye.
Purchasing from reputable jewelers or gem dealers is highly recommended, as they can provide certification or guarantee authenticity. If a deal for a large, high-quality moonstone with strong blue flash seems unusually inexpensive, it is likely too good to be true, as genuine moonstone with desirable optical effects commands a higher price.