Malachite
Malachite is the most immediately recognisable stone we set, and the one that most rewards being looked after.
What causes malachite's banding?
Malachite is a copper carbonate that forms in the weathered upper zones of copper deposits — it is, in effect, copper rusting slowly in the presence of carbonated groundwater. It grows in botryoidal masses: rounded, grape-like lobes building outward in layers. Slice through those lobes and you get the concentric bands, from near-black through to bright verdigris, that no other stone produces.
Every band is a growth interval. The pattern is a record of the chemistry of the water at the time, which is why the same deposit produces the same character and different deposits do not.
Was malachite used as a pigment?
Ground malachite was one of the oldest green pigments in use, on Egyptian tomb walls and in medieval panel painting, long before anyone was cutting it for rings. It fell out of pigment use because it is not lightfast in some binders — not a concern for a solid stone.
How soft is malachite, really?
Mohs 3.5 to 4. That is softer than a copper coin, softer than most things in a jewellery box, and soft enough that ordinary dust — which contains quartz at Mohs 7 — will dull the polish if you rub it in. Malachite is also sensitive to acid: lemon juice, vinegar and even prolonged sweat will etch the surface.
This is why we bezel-set it and use it in signet faces rather than raised claws. Set flush and surrounded by silver, it is protected from exactly the knocks that would damage it. A malachite ring is a fine thing to own; it is not a thing to wear gardening.
How do you care for malachite?
Wipe with a dry, soft cloth. That is the whole method. No ultrasonic cleaner, ever — vibration plus a soft banded stone is how malachite cracks along its layers. No steam. No commercial jewellery dip. If it genuinely needs more, a barely damp cloth and immediate drying. Store it in its own pouch.
Is malachite safe to wear?
Cutting malachite produces copper-bearing dust that is not good to breathe, which is why our cutters work wet. The finished, polished stone is entirely safe to wear — this is a workshop concern, not a wearer's one, but people ask.