Kyanite is a striking metamorphic mineral prized for its beautiful blue color and unique crystal structure, making it popular for both jewelry and industrial applications. Since kyanite is often worn daily, its durability regarding water exposure is a common concern. Whether kyanite can get wet is nuanced, depending on the duration of exposure, the water’s composition, and the physical stresses applied to the stone. Understanding the mineral’s structure provides the necessary context for proper care.
Kyanite’s Chemical and Physical Structure
Kyanite is an aluminum silicate mineral (\(text{Al}_2text{SiO}_5\)). This highly stable composition means the mineral does not dissolve or chemically degrade when exposed to plain water. Therefore, the primary consideration for kyanite’s interaction with water is not its chemistry, but its unique physical structure, particularly its anisotropic hardness and perfect cleavage.
The mineral exhibits anisotropic hardness, meaning its scratch resistance varies significantly depending on the direction it is tested. Along the length of the crystal, parallel to its long axis, kyanite is relatively soft (4 to 4.5 on the Mohs scale). However, perpendicular to the long axis, the hardness increases sharply to 6 to 7.5, comparable to quartz. This variation in hardness, combined with its perfect cleavage along one plane, creates a structural weakness that requires careful handling.
The Direct Impact of Water Exposure
While kyanite’s chemical makeup is stable in water, prolonged soaking can cause physical damage. The most significant risk stems from the stone’s perfect cleavage, which is a predisposition to split along planes of atomic weakness. This structural vulnerability makes kyanite susceptible to internal fracturing from sudden temperature fluctuations, known as thermal shock. Exposing the stone to rapid temperature changes can cause differential expansion, initiating a fracture along its cleavage plane.
Water also introduces risks when kyanite is set in jewelry. Many pieces use adhesives, which prolonged soaking can weaken or dissolve, causing the stone to become loose. Furthermore, metal settings, especially silver or plated materials, are vulnerable to corrosion or tarnishing when exposed to moisture. Water containing chemical additives presents a greater threat to both the setting and the stone.
Chemically treated water, such as chlorinated pool water, or naturally occurring saltwater, should be avoided. These substances accelerate the corrosion of metal settings and may leave residue on the stone’s surface, dulling its luster. Some blue kyanite contains trace iron or chromium impurities, which could potentially oxidize if repeatedly exposed to moisture. A quick rinse is permissible, but soaking is not recommended.
Safe Handling and Cleaning Practices
Proper care for kyanite involves minimizing water exposure and avoiding conditions that exploit its structural weaknesses. The safest method for cleaning kyanite is a gentle wipe with a soft, clean cloth. If deeper cleaning is necessary, use a mild soap solution mixed with lukewarm water.
The stone should be briefly dipped and gently rubbed to remove surface dirt. Follow this with an immediate and thorough rinse in clean, lukewarm water to remove all soap residue. Crucially, the kyanite must be dried immediately afterward using a soft, lint-free cloth to prevent water from lingering in fissures or around the setting.
Because of the risk of thermal shock and perfect cleavage, cleaning devices must be avoided. Ultrasonic cleaners and steam cleaners can cause the stone to crack or shatter due to vibrations and high heat. To protect the stone and its setting, kyanite jewelry should always be removed before swimming, showering, or engaging in strenuous activity where it could be exposed to harsh chemicals.