Moissanite has emerged as a popular alternative to diamonds, captivating many with its brilliance and durability. A common question among those interested in this gemstone concerns its reaction to ultraviolet (UV) light.
Moissanite’s Reaction to UV Light
Moissanite can exhibit a glow when exposed to ultraviolet light, a phenomenon known as fluorescence. This glow can manifest in a range of colors, most commonly appearing as yellow or green. Less frequently, moissanite may display a blue hue, and occasionally, an orange or white glow can be observed. The intensity and specific color of this emitted light can vary significantly from one moissanite stone to another.
The variability in moissanite’s fluorescence depends on factors such as the stone’s inherent properties, including its crystal structure and composition. It is important to note that not all moissanite stones will fluoresce under UV light. Stones that are free from certain foreign materials or lattice imperfections may not visibly glow. The glow, when present, is a stable characteristic of the stone.
Understanding Gemstone Luminescence
Gemstone luminescence refers to the emission of light by a gemstone after it has absorbed energy, typically from an external source like ultraviolet light. This occurs when certain atoms or ions within the gemstone’s crystal structure absorb UV radiation. When these electrons absorb UV energy, they temporarily jump to a higher energy level. As these excited electrons return to their original, lower energy state, they release the absorbed energy as visible light, creating the observed glow.
Two primary types of luminescence are fluorescence and phosphorescence. Fluorescence is the immediate emission of visible light while the UV light source is present. The glow ceases almost immediately once the UV source is removed. Phosphorescence involves a delayed release of this energy, meaning the gemstone continues to glow for a period after the UV light source has been turned off. This afterglow can last from seconds to hours. The presence of trace elements, such as manganese or uranium, or structural imperfections within the crystal lattice, are often responsible for activating these luminescent properties.
Comparing Moissanite’s Glow to Diamonds
Both moissanite and diamonds can fluoresce under UV light, but their typical responses often differ. Diamonds commonly exhibit a blue fluorescence, which is observed in about 30% of natural diamonds. This blue glow can range in intensity from faint to very strong. Less often, diamonds may fluoresce yellow, green, or white. The blue fluorescence in diamonds is often linked to the presence of nitrogen atoms within their crystal structure.
In contrast, moissanite’s glow under UV light is typically described as a more varied and sometimes stronger phenomenon. While diamonds predominantly show blue, moissanite’s fluorescence tends to be more commonly in the yellow or green spectrum, though blue can also occur. The intensity of moissanite’s glow can also be more pronounced than that of diamonds.
Using UV Light for Moissanite Identification
While moissanite’s reaction to UV light can offer some clues, it is not a definitive standalone test for identification. The variability in moissanite’s glow, coupled with the fact that some diamonds also fluoresce, means that relying solely on a UV light test can be misleading.
For conclusive identification, gemologists rely on more comprehensive methods. These include examining the stone’s refractive index, which can reveal moissanite’s distinct double refraction. Professional tools that measure thermal conductivity and electrical conductivity are also used, as moissanite exhibits different properties in these areas compared to diamonds. While observing a glow under UV light is an interesting characteristic, professional gemological testing is essential for accurate and reliable identification.