Onyx

What we make

Our most technical onyx job is the floating backlit staircase, treads lit from inside and fixed into the wall. We also make lit wall panels, bar and reception counters, vessel basins and coffee tables.

Thickness and backing

We usually work it at 2 cm. At 3 cm and more, far less light gets through. Onyx breaks easily and often has natural cracks, so slabs nearly always come with a fibreglass mesh on the back, or bonded to laminated glass when they're lit. At 2 cm it weighs about 54 kg per m² before the backing, and the wall fixings are worked out from that.

Lighting

Behind the stone go LEDs and a diffuser. The further back the light, the more even it looks, and the deeper the box gets. The power supply stays reachable and away from wet areas. A honey slab looks brown in daylight and orange once lit, so we always pick the colour with the slab lit from behind, a torch at the very least. That's also when the cracks show.

What we advise against

Kitchen worktops, busy floors and anything outdoors. Onyx scratches and breaks more easily than marble and lemon marks it just the same. For a bar counter with glasses and lemon slices going round all evening, a translucent resin is the sensible choice. For a lit wall, natural onyx has more depth.

Care

Neutral soap and a soft cloth, nothing acidic. In a bathroom, wipe it after use, as hard water dulls the polish. Light scratches polish out and a crack can be stabilised with resin.

To see an onyx slab lit up, come to the workshop in the ZI Ouest or call 07 45 20 76 39. See also marble staircases and clearance slabs.