Most crystal damage is not mysterious. It is chemistry and physics doing exactly what they do, and nobody telling you beforehand that sunlight bleaches amethyst, water dissolves selenite, or salt corrodes pyrite until the stone is already ruined.
Here are the five that come up constantly, what actually causes them, and whether anything can be done afterwards. (Short answer on that last part: usually no.)
This is the most common one, and it is both the easiest to prevent and the most upsetting because purple amethyst is usually the piece people paid the most for.
Cause: ultraviolet light. Amethyst’s purple comes from iron impurities in the quartz that were irradiated as the crystal formed. Enough UV and that colour centre breaks down. The stone turns pale grey-lavender, then near-white.
How long it takes: A few weeks of direct sun on a south-facing windowsill is enough to noticeably fade a good piece. Indirect daylight takes months to years. It is cumulative and permanent.
Prevention: Keep amethyst out of direct sun. A north-facing room, a shelf away from the window, or a cabinet with a door. If your altar must be on the sunny sill, put amethyst in the back row behind something that can take it — clear quartz, carnelian or smoky quartz are far more light-stable.
Can it be fixed? No. There is no safe home remedy for re-irradiating quartz. Keep the pale one as a lesson and buy a replacement.
Our amethyst wands and scepters are pieces people hold rather than display in a window, which is partly why they hold colour so well — but the rule still applies.
Selenite and satin spar are gypsum. Gypsum is soluble in water. It is a 2 on the Mohs scale — you can scratch it with a fingernail — and it will literally dissolve if you put it under a tap to “cleanse” it.
Cause: water. Even sustained high humidity will round the edges of a carved piece over months.
What it looks like: the sharp edges go soft and chalky, the surface goes milky, and a polished piece develops a rough, pitted skin. In a bad case the whole thing slumps.
Prevention: never wet it. Dust with a dry, soft brush. Keep it out of bathrooms. Cleanse with moonlight or sound instead.
General rule: if a mineral is soft enough to scratch with a fingernail, it does not go in water. That covers selenite, satin spar, desert rose, halite and most calcites.
“Fool’s gold” is iron sulphide. Add water and oxygen and you get sulphuric acid and iron oxide — rust. A raw pyrite nugget left in a salt bowl or rinsed under a tap will develop an orangy crust within days and start shedding gritty dust.
Cause: water, salt, humidity. Some pyrite specimens are unstable from the day they are mined and will decay regardless — a problem called “pyrite rot” that also plagues museum collections.
Prevention: keep it dry, keep it away from salt, and store it in a low-humidity room. If you want it on display in a damp house, seal it in a small display case with a silica sachet.
Same rule for hematite, magnetite, chalcopyrite, galena and anything with a metallic sheen: no water, no salt.
Cause: thermal shock. Stone expands when it warms. Heat one side quickly — a hot windowsill, a radiator, direct midday sun on a cold piece, or hot water followed by cold — and the differential stress finds the weakest internal flaw.
This is also how geode clusters lose chunks: someone runs hot water over them to clean out dust, and a crystal pops off. Beautiful, fragile, and impossible to glue back invisibly.
Prevention: never use hot water on stone. Lukewarm at most, never a sudden temperature change, never on a radiator or above an oven. Clean dust off clusters with a soft brush or a hairdryer on cool.
Bonus risk: freezing. A wet stone left outside overnight in freezing winter weather can crack as the trapped water expands. If you cleanse by burying, do it in summer and wrap the stone.
Angel aura, titanium aura, aqua aura — these are natural quartz with a vapour-bonded metal layer. That layer is on the surface, not inside.
Cause: abrasion, harsh cleaners, and ultrasonic jewellery cleaners. An ultrasonic bath will strip an aura finish in a minute. So will scrubbing with anything abrasive.
Prevention: dust with a soft cloth, never soak, never put it in an ultrasonic cleaner, take it off before swimming or showering. If it is set in jewellery, put it on last, after perfume and hairspray.
Worth saying plainly: the coating is real and the underlying quartz is real, but the colour is a surface treatment. That is why these pieces are cheap, and it is also why they need gentler handling than plain quartz.
Before you clean or cleanse any stone, ask two questions:
If the answer to both is no, cool water is almost certainly fine. When in doubt, moonlight and sound are safe for literally everything.
We list reconstituted (“smelting”) pieces as reconstituted, and treated pieces as treated, because the single most common cause of a ruined crystal is someone not knowing what they actually bought and treating a delicate thing like a lump of quartz. If you ever want to know what a piece is before you buy it, ask — and if you have already ruined one, tell us what happened; we would rather you knew than guessed.
Start with something indestructible while you get the hang of it: a clear quartz point or a box of raw stones will survive almost anything except being dropped on tiles.
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