Crystal Care by Mohs Hardness: Useful, but Not the Whole Story
Mohs hardness helps predict scratches, but it does not tell you whether a mineral dissolves, cleaves, fades or reacts with acid.
Mohs hardness helps predict scratches, but it does not tell you whether a mineral dissolves, cleaves, fades or reacts with acid.
What Mohs measures
The Mohs scale compares scratch resistance. Quartz at 7 can scratch fluorite at 4. A fingernail around 2.5 can scratch gypsum around 2.
Hardness is not toughness
A hard mineral can still cleave or fracture. Topaz is hard but has cleavage; fluorite is softer and also cleaves readily.
Hardness is not water resistance
Gypsum is soft and water-sensitive, but the broader point is that solubility, oxidation and treatments are separate properties. A “Mohs 6+ is water safe” rule is unreliable.
Use it for storage
Hardness is extremely useful for deciding what can scratch what. Keep soft polished minerals away from loose quartz points and metal objects.
Use species-specific care
The best care guide combines hardness, cleavage, chemical sensitivity, light stability, porosity, matrix and treatment history.
How we approach crystal claims
We document traditional and contemporary crystal associations because readers search for them, but we do not present those beliefs as established medical, psychological or financial effects. For care and authenticity questions, mineral identity and treatment history come first.
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