Onyx
slabs
The only stone we sell that is meant to be lit from behind. Onyx is translucent, banded and genuinely rare, and it turns a bar front or a powder room wall into the thing people photograph. ARCA holds 11 onyx pieces in Wynwood.
What we are holding
Every piece is one of one and inventory moves weekly, so treat this as a snapshot rather than a promise. Call the showroom and we will check the exact lots on the floor today while you are on the line.
Onyx in the showroom
Pulled from our live inventory system. Filter by finish, thickness or application, then tell us what you want staged before you arrive.
Why people specify it
Translucent, which nothing else here is
Onyx transmits light rather than reflecting it. Put an LED panel behind a 3/4 inch slab and the banding glows from inside the stone, in a way no printed porcelain and no backlit acrylic reproduces. This is why onyx shows up on bar fronts, reception desks, powder room walls and headboards rather than on kitchen counters.
Eight distinct onyxes, which is most of what exists here
Onyx forms slowly in caves and hot springs from dripping mineral water, so it comes out of the ground in small quantities and in blocks that are often fractured. We hold White, Ivory, Ivory Ice Vein Cut, Bianco, Green and Pink. When a stone is this scarce, the question is not which colour you want but which slab is available.
Lit in the showroom before you commit
A photograph of onyx is close to worthless, because the whole material changes when light passes through it rather than bouncing off it. A slab that looks pale and quiet under showroom lights can turn amber and dramatic backlit. Tell us onyx when you book, we will light the slabs for you, and your shortlist holds for 48 hours.
How to specify it properly
Onyx is a banded calcite that forms in caves and around hot springs, deposited layer by layer from dripping mineral-rich water in the same process that builds stalactites. That slow, still formation is what produces the parallel banding and, more importantly, the translucency: the crystal structure is regular enough to let light pass through rather than scatter it back. It is the reason a slab of onyx behaves more like alabaster or stained glass than like a countertop material.
It is also soft and often fractured. Onyx sits around 3 on the Mohs scale, well below marble, and it is an aggressive calcite, so it etches quickly and scratches easily. Blocks frequently come out of the ground with natural fissures, and slabs are commonly reinforced with a fibreglass mesh backing to survive transport and fabrication. None of that is a defect being hidden from you. It is the normal condition of the material and any honest supplier will show you the back of the slab.
Backlighting is where onyx earns its keep, and it needs planning that starts before the slab is cut. You want an even, low-heat LED panel set back far enough that individual diodes do not read through the stone as hot spots, usually somewhere around two to four inches with a diffuser. Thinner stone glows more, so book-matched onyx is often resawn. The banding you see under showroom lighting is not the pattern you will get lit, which is why we light it for you in person.
The honest limitation: this is not a kitchen counter. Onyx belongs on vertical and low-contact surfaces, bar fronts, reception desks, powder room vanities, feature walls, headboards and backlit panels. Specified there it will outlast the building. Specified on a working island it will etch within a week and scratch within a month. Clients who want the look on a hard-working surface get shown Cristallo quartzite instead, which is translucent, takes backlighting, and is more than twice as hard.
Specification
- Material
- Natural onyx, banded translucent calcite
- In stock
- White Onyx, Ivory Onyx, Ivory Ice Vein Cut, Bianco, Green Onyx, Pink Onyx
- Formats
- Full slabs
- Finishes in stock
- Honed and Polished
- Thickness
- 3/4 inch (2cm)
- Hardness
- Around 3 on the Mohs scale, softer than marble
- Typical use
- Backlit panels, bar fronts, reception desks, powder room vanities, feature walls, headboards
- Care
- Seal on install. Not recommended for kitchen counters or high-traffic floors.
Onyx, answered
See a stone you want? Book a private visit: your slabs get pulled and staged, and your shortlist holds for 48 hours under First Look.
Get Showroom AccessSee the collection
in person
Every ARCA slab is one of one, and booked visits see them first. Pick your time instantly — your specialist stages your slabs before you arrive and unlocks First Look access to stone the floor has not seen yet.
Prefer to talk? Call the showroom+1 (786) 460-7444 · answered 24/7Wynwood, Miami, FL 33127