Reference
Water-Safe Crystals
Which crystals can go in water and which will dissolve, corrode, or release toxins? The complete reference for 350 crystals, based on mineral chemistry and hardness, with a salt water verdict for every stone and the verified sunlight sensitivity list.
Water Safe
Brief Rinse Only
Avoid Water
Dissolves in Water
Why Some Crystals Cannot Get Wet
Water damages minerals through four mechanisms, and many collectors learn this the hard way.
Dissolution
Some minerals are water-soluble. Selenite (gypsum), halite (rock salt), and some sulfates literally dissolve when submerged. Selenite will develop surface etching in minutes.
Chemical Reaction
Iron sulfides (pyrite, marcasite) react with water and oxygen to form sulfuric acid, which corrodes the specimen and can damage surrounding stones. Copper carbonates (malachite) can release toxic copper compounds.
Absorption
Porous minerals (turquoise, opal) absorb water like a sponge. This changes color permanently, carries contaminants into the stone, and can cause cracking as trapped water expands and contracts with temperature changes.
Structural Damage
Minerals with perfect cleavage (mica, kyanite, moonstone) can trap water between structural layers. When temperature changes, the water expands and forces the layers apart. Soft minerals can also erode from water flow.
The Hardness Rule of Thumb
A common guideline is that minerals with Mohs hardness 6 or above are generally water-safe, while those below 5 should be kept dry. This is a useful starting point but has important exceptions.
Exceptions to the rule: Pyrite is hard (6-6.5) but reacts chemically with water. Opal is moderately hard (5.5-6.5) but absorbs water through its porous structure. Turquoise is hard enough (5-6) but is extremely porous. Conversely, gold is very soft (2.5-3) but completely water-safe because it is chemically inert.
The real question is not just "is it hard?" but also "is it chemically reactive?" and "is it porous?" Hardness alone is not enough.
What About Salt Water?
Salt water is harsher than plain water for every mineral on this page. Dissolved salt is corrosive while the stone is wet, and as the water evaporates it leaves abrasive salt crystals behind in cracks, crevices, and around settings. Iron-bearing stones rust faster in salt water, copper-bearing stones corrode faster, and porous stones absorb the salt itself.
The honest general rule: hard, non-porous stones (quartz and its relatives) tolerate a brief dip if you rinse them with fresh water afterward and dry them, but salt water soaking is not recommended for any stone. Everything rated "Brief Rinse Only" or worse for plain water is a firm no for salt water. Every stone in the lists below carries its own salt water verdict chip, and each crystal's profile page answers the salt water question in full.
A Note on Crystal Water and Gem Elixirs
Placing crystals directly in drinking water is dangerous with many minerals. Malachite releases copper. Galena releases lead. Cinnabar releases mercury. Realgar and orpiment release arsenic. Even minerals not typically considered toxic can release trace elements or particles you do not want to ingest.
If you choose to make gem elixirs, use the indirect method: place the crystal in a separate sealed glass container, then place that container in the water. The crystal never contacts the drinking water. This eliminates any risk of contamination.
Never place the following in drinking water under any circumstances: malachite, azurite, galena, vanadinite, wulfenite, crocoite, cinnabar, realgar, orpiment, stibnite, bumble bee jasper, mimetite, adamite, pyromorphite, erythrite, or any mineral containing lead, arsenic, antimony, or mercury.
Water Safe
(217 minerals)Safe for water cleansing, brief soaking, and cleaning with mild soap and water.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 8.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.25. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 8. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 8.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 8.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 10. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.25. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.25. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.75. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.75. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 8. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 9.25. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 8. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 9. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 8. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 9. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 7.25. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Moderately durable. Safe for water contact and gentle cleaning.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 8. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 9. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 9. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.25. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 8. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 9. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 9. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 8. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Moderately durable. Safe for water contact and gentle cleaning.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 8. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.25. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 9. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Hardness 7.5. Chemically stable silicate. Safe for water cleansing, brief soaking, and cleaning with mild soap.
Brief Rinse Only
(43 minerals)Quick rinse under running water is acceptable. No soaking or prolonged submersion.
Hardness 3.5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 6. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 4. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 3.25. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 3.5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 4.5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Calcium fluoride is slightly water-soluble over long exposure. Brief rinse is fine, but avoid prolonged soaking.
Hardness 4.5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 3.5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Safe in brief water contact but the real danger is sunlight exposure, which permanently fades the color.
Variable hardness (4.5-7 depending on direction). Water can penetrate along weak cleavage planes. Brief rinse only.
Feldspar with internal layered structure. Brief rinse is safe but avoid soaking, as water can penetrate cleavage planes.
Hardness 5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 4. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Feldspar with cleavage planes. Water can seep into micro-fractures and expand during temperature changes, causing cracking.
Hardness 4.5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Contains up to 20% water internally. Soaking can cause differential expansion and cracking (crazing). The water content is structural.
Hardness 5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 4.5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 4.5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 4.5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 4. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 3.5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 4.5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 3.5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 6.5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 4. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 4.5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 3.5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 5. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Hardness 4. Quick rinse under running water is acceptable. Avoid soaking or submersion. Dry thoroughly afterward.
Avoid Water
(82 minerals)Water can damage, stain, corrode, or degrade. Clean with dry cloth only.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Organic gem (fossilized resin). Water will not dissolve it, but prolonged soaking can cause surface cloudiness and cracking.
Very soft (Mohs 2.75). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Same composition as calcite (CaCO₃) but less stable crystal structure. Dissolves in acid and degrades in water.
Very soft (Mohs 3). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 2). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Very soft (Mohs 2.5). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 2.5). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 2.5). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 3). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Calcium carbonate dissolves in acidic water. Even slightly acidic tap water will etch the surface over time.
Very soft (Mohs 3). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Strontium sulfate. Slightly water-soluble, extremely fragile, and fades in light. Handle as little as possible.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Very soft (Mohs 3). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 2.5). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 2.5). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
TOXIC. Mercury sulfide. Water can release mercury compounds. Handle briefly, wash hands immediately.
Very soft (Mohs 3). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Calcium carbonate skeleton of marine organisms. Acids, soap, and prolonged water contact damage the surface.
Very soft (Mohs 1.5). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Very soft (Mohs 2.5). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 2.5). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Very soft (Mohs 2). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 2.5). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Not because gold reacts: it is chemically inert and does not corrode. But native gold is very soft (Mohs 2.5) and specimens often sit on fragile matrix that wet handling can damage. Clean with a dry soft brush instead.
Very soft (Mohs 3). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Iron oxide can rust when submerged. Brief rinse is tolerable but prolonged soaking causes surface deterioration.
Very soft (Mohs 3). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Iron-nickel alloy that rusts aggressively in water. Store with desiccant packets. Never submerge.
Very soft (Mohs 3). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Contains pyrite (iron sulfide) and calcite (acid-soluble carbonate). Both degrade in water. The pyrite can rust and stain.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Mica structure delaminates (separates into layers) when wet. Water gets between the layers and stays.
Very soft (Mohs 3). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Copper carbonate that releases toxic copper compounds in water. Never use for gem elixirs. Brief rinse acceptable for cleaning but dry immediately.
Very soft (Mohs 3). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 3). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Chemically unstable iron sulfide. Decomposes in humidity, producing sulfuric acid. Keep as dry as possible.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Very soft (Mohs 2.5). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 2.5). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 2). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 3). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 3). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 3). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Organic gem made of calcium carbonate layers (nacre). Water, soap, and chemicals degrade the nacre over time.
Very soft (Mohs 2.25). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Iron sulfide reacts with water and oxygen to form sulfuric acid. This corrodes the specimen and can produce a sulfur smell. Keep dry.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
TOXIC. Arsenic sulfide. Decomposes in light and water. Store in darkness. Handle with extreme caution.
Manganese carbonate. Acid-soluble and soft. Water contact causes surface dulling over time.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Very soft (Mohs 2.5). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Silver tarnishes by reacting with sulfur compounds, and moisture accelerates the process. Wipe native silver with a dry cloth and store it in anti-tarnish cloth rather than washing it.
Very soft (Mohs 1.5). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 2). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 1.5). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Avoid water contact. May react, absorb moisture, or degrade. Clean with dry or slightly damp cloth.
Very soft (Mohs 3). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 1). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Extremely porous. Absorbs water, oils, soap, and chemicals, all of which permanently change its color. Keep dry.
Very soft (Mohs 2.5). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 3). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 2). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Very soft (Mohs 3). Water can damage, dissolve, or degrade the surface. Clean with dry cloth only.
Dissolves in Water
(8 minerals)Water-soluble. Even brief contact or high humidity can cause permanent damage.
Reverts to gypsum when exposed to water. Will lose its blue color and smooth texture permanently.
A selenite variety. Water-soluble and extremely fragile. Never expose to moisture.
Water-soluble. This includes selenite towers, satin spar, and desert roses. Never use water for cleaning.
Fibrous gypsum (CaSO₄·2H₂O), water-soluble like selenite. Even brief contact dulls the silky luster.
Dissolves in water. Selenite is a form of gypsum (CaSO₄·2H₂O), which is water-soluble. Even brief contact can etch the surface.
Which Crystals Are Sensitive to Sunlight?
Light-sensitivity claims circulate for almost every crystal, and most have no documented basis. The 38 stones below are the ones in our encyclopedia whose behavior in light is documented in the mineralogical literature, verified against the same sources the profiles cite.
A stone missing from this list has no documented light sensitivity, which is not the same as a guarantee. Each listed stone's profile answers its sunlight question in full.
Fades Permanently in Sunlight
(19 stones)Prolonged direct sun gradually bleaches the color centers in these stones, and the lost color does not come back. Daily handling in daylight is fine; a permanent sunny windowsill is not.
Purple color centers bleach gradually and permanently in strong light.
Both the purple and yellow zones are light-sensitive and can slowly pale.
Stable except the rare deep-blue Maxixe type, which fades dramatically.
The delicate sky blue fades permanently with prolonged sunlight.
Nickel-green can pale with heat and sun, partly through dehydration.
UV-sensitive, and heat-treated material is not fully color-stable either.
Some varieties, notably certain blues and greens, pale with prolonged sun.
The purple form fades like amethyst in prolonged direct sun.
The green can gradually fade with light, like its sister stone kunzite.
Some stones fade with extended sun exposure. Not a windowsill stone.
The textbook fader. Store it in the dark when not wearing it.
The blue is photosensitive and fades with too much light and heat.
The soft pink can pale gradually with prolonged direct sun.
Can pale slowly under prolonged direct sun; the change is permanent.
Irradiation-induced color fades with UV exposure or strong heat.
Mostly amethyst-colored, so the purple fades with prolonged sun.
Sherry yellow-brown stones can fade; blue and colorless are stable.
Sun can discolor or dehydrate it, shifting blue material toward green.
Fades like all amethyst, and the pale lavender has little color to spare.
Heat and Dehydration Sensitive
(12 stones)For these, the light itself is mostly harmless; the heat and dryness of direct sun are the problem. Opals and pearls can dehydrate and crack, and amber oxidizes and darkens. A shaded display spot keeps them safe.
Sun and heat oxidize the resin, darkening it and crazing the surface.
Treated matrix is stable; untreated crystal opal needs standard opal caution.
Sun excites the blue glow, but prolonged exposure oxidizes and crazes the resin.
The ironstone matrix is sun-proof; the opal veins can still craze with heat.
Sun dehydration risks crazing. Backlight it with a lamp instead.
Heat and dehydration risk crazing, though it is somewhat more stable than most opal.
Prolonged sun dehydrates it; the color dulls and fine cracks can form.
The matrix stabilizes it, but the opal veins can craze with prolonged heat.
Prolonged sun heat dehydrates it, which can cause permanent crazing.
Generally stable to light, but heat from intense light dehydrates and cracks nacre.
Prolonged sun dehydrates it, dulling the color and risking crazing.
Sustained sun dehydrates it, paling the pink and risking fine cracks.
Darkens or Decomposes in Light
(5 stones)Light chemically alters these minerals, irreversibly darkening or breaking down the surface. Collectors store them in darkness and view them briefly. Several are also toxic, so wash your hands after handling.
Light gradually darkens it toward black. Keep displays dim.
Light-sensitive arsenic sulfide that deteriorates with prolonged exposure.
Scarlet crystals turn dull black with light exposure. Store in darkness.
Light converts it to crumbly pararealgar, irreversibly. Store in darkness.
Oxidizes and darkens irreversibly toward black with light exposure.
Tenebrescent (Reversible Color Change)
(2 stones)These rare minerals change color in sunlight and change back in the dark. That is reversible physics, not damage, and collectors often manage the color with deliberate light exposure.
Tenebrescent: bleaches or deepens in sunlight depending on locality, reversibly.
Tenebrescent: pink-red deepens in sunlight and fades in the dark, reversibly.
Alternative Cleaning Methods
For crystals that cannot go in water, these methods are safe for cleaning and maintenance.
Dry Cloth
A soft microfiber cloth removes dust and fingerprints from any specimen without risk. The safest universal method. Use gentle pressure and avoid rubbing soft minerals aggressively.
Compressed Air
A can of compressed air or a soft bellows removes dust from delicate crystal surfaces, cluster crevices, and fragile specimens. Keep the can upright to avoid propellant spray.
Soft Brush
A clean, soft-bristled brush (watercolor brush, makeup brush) can gently sweep dust from textured surfaces and crystal clusters. Never use a stiff brush on soft minerals.
Slightly Damp Cloth
For minerals rated "Brief Rinse Only," a barely damp cloth provides cleaning power without submersion risk. Wring out the cloth thoroughly and dry the specimen immediately afterward.