Rock IdentifierCleaning & Caring for Specimens
Key takeaways
- Start with the gentlest method: warm water and a soft brush.
- Some minerals dissolve in water, fade in sunlight, or are damaged by ultrasonic cleaners.
- Store soft and light-sensitive stones carefully, separated from harder ones.
Gentle first, always
Most specimens only need lukewarm water, a drop of mild dish soap, and a soft toothbrush to lift dirt from crevices. Rinse and let air-dry. Escalate to stronger methods only when necessary, and never start with anything harsh — you can't undo a scratch or an etched surface.
Minerals that hate water
Water-soluble or water-sensitive minerals can be dulled or destroyed by a simple rinse. Halite (rock salt) literally dissolves. Selenite and other gypsum varieties are soft and can cloud or cleave. Many delicate specimens are better cleaned with a dry, soft brush or just canned air. When in doubt about a soft or fibrous mineral, keep it dry.
- Avoid water: halite, selenite/gypsum, and other soluble salts
- Avoid ultrasonic cleaners: opal, emerald, turquoise, pearls, and fracture-filled stones
- Avoid acids: calcite, malachite, and most carbonates (they fizz and etch)
Light, heat, and fading
Prolonged sunlight fades some minerals irreversibly. Amethyst, rose quartz, celestite, fluorite, and many dyed stones can lose color on a sunny windowsill. Opal can craze (develop tiny cracks) if it dries out or overheats. Display light-sensitive pieces away from direct sun, and avoid sudden temperature changes that can crack a specimen.
Handling and storage
Harder minerals scratch softer ones, so don't store them jumbled together — wrap individually or use divided trays. Support heavy pieces so fine crystals aren't bearing weight. Keep a small label with each specimen's name and locality; that record is easy to lose and hard to recover, and it's part of what makes a collection meaningful.
