Built by a geologist
How to Clean Rocks and Minerals Without Destroying Them
Cleaning a rock or mineral specimen begins with deciding whether any cleaning is justified. Geological material is not automatically inert or durable. A specimen may include water-soluble salts, swelling clays, delicate crystal attachments, cleavage, pores, fractures, reactive sulfides, toxic elements, radioactive phases, fibrous minerals, treatments, adhesives, dyes, oils, waxes, fillers, coatings, culturally or scientifically significant material, or an unknown matrix. Photograph every dry surface with scale, assign a field or catalog number, retain the original label and locality record, and document identity, condition, rights, value, treatments, repairs, and the proposed reason for intervention before removing anything. Matrix, weathering, soil, residues, coatings, fusion crust, pigments, corrosion products, and earlier preparation can preserve identification, provenance, or research evidence. Prefer preventive storage and dust control over repeated cleaning. Stop and seek appropriate specialist help for unknown, valuable, fossil, artifact, meteorite-candidate, type, research, mounted, repaired, treated, fragile, porous, fractured, soluble, reactive, actively deteriorating, radioactive, fibrous, toxic-metal-bearing, arsenic-, mercury-, lead-, beryllium-, thallium-, cadmium-, selenium-, mouldy, industrially contaminated, or mine-waste material. New powder, crystals, salts, weeping, odour, heat, corrosion, container damage, or colour change can indicate deterioration rather than dirt. Water is not a universal safe cleaner: halite and other salts dissolve, gypsum is soluble, clays can swell, porous matrix can retain moisture, and treatments, labels, adhesives, coatings, inclusions, and mixed phases may change. Do not improvise acids, vinegar, bleach, ammonia, peroxide, solvents, detergents, drain cleaners, rust removers, heat, steam, ultrasonic vibration, pressure washing, wire brushing, sanding, grinding, blasting, drilling, polishing, or compressed air. Chemicals can react with the specimen, each other, contaminants, containers, and waste; abrasion and dried slurry can create respirable silica, fibres, toxic dust, projectiles, or contaminated water. If authoritative material-specific guidance independently establishes a known common specimen as intact, stable, safe, and compatible, only a hidden documented minimal dry or water spot test may be justified.