Moonstone, a feldspar mineral, exhibits a unique optical phenomenon called adularescence, creating a shimmering glow across its surface. This captivating effect makes it a popular choice for jewelry. Understanding its physical properties helps determine its suitability for daily wear and how to maintain its beauty over time.
Moonstone’s Inherent Durability
The intrinsic durability of a gemstone is primarily determined by its hardness and cleavage. Moonstone has a hardness rating of 6 to 6.5 on the Mohs scale, which measures a mineral’s resistance to scratching. This places it above common household dust, which contains quartz (Mohs 7), meaning moonstone can be scratched by everyday dust if not stored properly. Compared to harder gemstones like sapphire (Mohs 9) or diamond (Mohs 10), moonstone is more susceptible to surface abrasions.
Moonstone also possesses perfect cleavage, which means it has distinct planes along which it can split cleanly when subjected to impact. This characteristic makes moonstone vulnerable to chipping or breaking if struck sharply against a hard surface. While it resists scratching reasonably well for its hardness, a direct blow can cause damage along its cleavage planes. Therefore, moonstone requires more careful handling than gems without cleavage or with less pronounced cleavage.
Moonstone is stable to light and most common chemicals encountered in daily life. However, it can be sensitive to extreme temperature changes, which may cause thermal shock and potential fracturing. Strong acids and alkaline solutions should also be avoided, as they can potentially damage the stone’s surface.
Factors Influencing Moonstone’s Durability
Beyond its inherent physical properties, several external and internal factors affect moonstone’s practical durability. The presence of inclusions, which are internal fractures, foreign minerals, or stress lines within the stone, can compromise its structural integrity. These internal weaknesses make the moonstone more prone to breakage, even from minor impacts, as they act as stress points. Gemstones with fewer or smaller inclusions are generally considered more durable.
Moonstone is typically not subjected to extensive treatments that alter its stability, as most specimens are valued for their natural adularescence. However, some lower-quality moonstones might be dyed to enhance their color or coated to improve luster. Such treatments, if present, could affect the stone’s long-term stability or require specific cleaning methods.
The type of jewelry setting plays a substantial role in protecting moonstone from damage during wear. Bezel settings, which completely encircle the gemstone with a metal rim, offer the most protection against impacts from the sides and top. Other protective settings include flush settings, where the stone is set into the metal, and channel settings, which protect the edges of the stone within a metal channel. Prong settings, while showcasing more of the stone, offer less physical protection and may expose the moonstone to potential chips or scratches.
Caring for Moonstone
Proper care and maintenance are important for preserving moonstone’s beauty and longevity. For cleaning, moonstone jewelry should be washed using mild soap and warm water with a soft brush or cloth. Harsh chemicals, such as bleach or abrasive cleaners, can dull the stone’s surface or cause damage, and should be avoided. Ultrasonic cleaners and steam cleaners are also not recommended, as the vibrations or high heat can exacerbate existing fractures or cause new ones, particularly due to moonstone’s cleavage.
Storing moonstone correctly helps prevent scratches and chips. It is best to store moonstone jewelry separately from harder gemstones like diamonds or sapphires, as these can easily scratch the moonstone’s surface. Wrapping moonstone pieces in a soft cloth pouch or placing them in a fabric-lined jewelry box will provide adequate protection. This prevents contact with other jewelry pieces that could cause abrasion.
Adopting careful wearing habits contributes significantly to moonstone’s durability in everyday use. It is advisable to remove moonstone jewelry before engaging in strenuous activities, such as sports, gardening, or housework, which could expose it to impacts or harsh chemicals. Similarly, removing moonstone rings or bracelets during activities that involve contact with hard surfaces, like typing or cooking, can prevent accidental chipping.