Material · Riverside, CA
Backlit Onyx Countertops in Riverside, CA, Built as a Statement Surface
Riverside Custom Countertops fabricates and installs onyx countertops in Riverside, CA. We handle slab selection, digital templating with dxf files, resin and mesh backing, seam planning, edge profiles, sink cutouts, backsplash fabrication, and the sealing and polishing this stone needs more than most. Onyx is not a workhorse surface.
It is the piece guests notice from the doorway, so we build it where light gets behind it: island waterfalls, bar fronts, powder room vanities, feature walls and reception desks.
Our crews cover the whole city, from Canyon Crest and Mission Grove out to Arlanza and La Sierra, and work across Riverside County along State Route 91 and Interstate 215.
Get your free written quote
Send your details and we reply the same business day. No obligation, and the estimate is in writing.
Or call (951) 589-3336 — calls only, we don't receive text messages.
Thanks, we have your request.
We reply the same business day, Monday through Saturday. For same-day scheduling call (951) 589-3336.
Free written estimate
Digital templating
Cut in our Riverside shop
Licensed & insured
01
Read This First: Most Countertop "Onyx" Is Not True Onyx
The stone the countertop trade sells as onyx is usually not true onyx. Almost nobody selling slabs leads with that.
True onyx is chalcedony: cryptocrystalline, fine intergrowths of quartz and moganite, Mohs 6.5 to 7. Genuinely hard stone, and far less available than what the trade calls onyx.
The material marketed as "onyx marble" or "Mexican onyx" is calcite. Different rock, and the majority of items sold as onyx today are that calcite material. Calcite behaves like marble, because it is chemically the same family: soft, porous and acid sensitive. Wine, lemon juice and many household cleaners etch it.
Ask your supplier one question, in writing: is this chalcedony onyx or calcite onyx marble? The answer changes the hardness, the maintenance schedule and where the slab belongs in your house.
| True onyx (chalcedony) | "Onyx marble" (calcite) | |
|---|---|---|
| Mineralogy | Cryptocrystalline quartz and moganite | Calcium carbonate, marble's family |
| Hardness | Mohs 6.5 to 7 | Soft, marble range |
| Acid behavior | Silica based, far more stable | Etches from acids and alcohol |
| Availability | Limited | What most "onyx" slabs actually are |
| Honest use | Statement surfaces, not a prep counter | Low traffic, sealed and babied |
02
What Onyx Looks Like, and Why
True onyx shows parallel bands in contrasting colors, classically black and white. Sardonyx, the related variety, shows red to brown bands with black or white stripes. Luster runs vitreous to silky, and the stone is translucent, which is the whole reason people want it.
One more honesty note. Most commercial black onyx is artificially colored using historical techniques. Not a defect, but be skeptical of anyone selling a jet black slab as naturally that color.
03
Backlighting: How the Glow Gets Built
The translucency is the product. Everything else follows from it.
Standard shop practice, and this is trade practice rather than a published spec, is an even LED panel in the cabinet or pedestal behind the slab, set with a small air gap so individual diodes do not read as hot spots. Thinner stone passes more light, so a 2cm (3/4 inch) slab transmits differently than a 3cm (1 1/4 inch) one, and the thinner 1.2cm and 6mm formats get used where light has to carry. Thinner also means weaker.
Onyx slabs are routinely reinforced on the back with resin and fiberglass mesh before cutting, to hold the stone through transport and fabrication. Common practice again, not a code requirement. That backing changes how light reads, so we light a corner of your slab before committing the layout, then cut with routers, grinders and CNC off a digital layout you approve.
04
Where Onyx Belongs in a Riverside Home or Business
Onyx earns its place where it gets seen and does not get worked.
- Backlit island fronts and waterfall panels. The face glows while a harder top carries the work surface.
- Bar fronts and home bar tops. Light behind the panel, little prep, high payoff.
- Powder room vanities. Low use, high impact. See bathroom vanity tops in Riverside.
- Feature walls, fireplace surrounds and niches. No standing water, no knives.
- Reception desks and hospitality millwork. A lit desk face reads expensive from across a lobby, which is the point. See our commercial countertop work.
Where it does not belong: the main kitchen run. Not the sink deck, not the cooktop landing, not the cutting zone. If your slab is calcite onyx marble, that limit is firm. Even chalcedony onyx is a banded, fissured, resin-backed stone we would not set behind a busy family sink in Orangecrest.
If the counter has to work for a living, cross-shop marble countertops. Marble is the other calcite luxury surface, it etches the same way, and it is far easier to source.
05
Onyx Compared to What Buyers Cross-Shop
| Material | Hardness | Sealing load | Backlights | Relative investment |
|---|---|---|---|---|
| Onyx (chalcedony) | Mohs 6.5 to 7 | Regular | Yes, its main use | Premium |
| Onyx marble (calcite) | Soft, marble range | Frequent | Yes | Higher to premium |
| Marble | About Mohs 3 | Regular, essential | Rarely | Higher |
| Quartzite | Harder and more stain resistant than granite | Periodic | No | Higher |
06
Finishes, Edges and Slab Formats
Polished is the default, because polish is what makes the translucency read. Honing dulls the glow.
Natural stone runs 2cm and 3cm as the common thicknesses, with 1.2cm and 6mm for cladding and lit panels and 4cm for built-up looks. Marble-format slabs commonly run 3050 x 1240mm, which sets panel size before seams enter it. Edges include bullnose, ogee and eased profiles. Fancier edges cost more, and on banded stone an aggressive profile cuts straight through the band you bought the slab for.
07
What Drives Your Investment
The slab drives everything. Factors that move your number: slab grade, rarity and banding quality, slab count and yield, thickness, resin and mesh backing, edge profile, seams, cutouts, backlighting build-out and the electrical behind it, tear-out and disposal, backsplash, plumbing reconnect, overhang brackets, and delivery access including stairs. All of it lands in a free written quote before we cut.
08
Care, Sealing and Honest Maintenance
Natural stone needs sealing to keep it from harboring bacteria and fluids, and with oleophobic impregnators most materials go five to ten years between treatments. Onyx is not most materials. A calcite slab in a bar or vanity wants a tighter schedule, and acidic spills need wiping now, not later. Neutral or mild alkali cleaners only, never acidic, never abrasive. Our countertop sealing and polishing service handles resealing, and countertop repair catches chips early.
09
Our Process and Service Areas
Slab walk, digital template, lighting mockup, fabricate, install. Onyx runs through countertop fabrication with more shop time than a granite top, because reinforcement and band matching cannot be rushed. Swaps go through countertop replacement, remodels through kitchen countertop installation.
| Area we serve | County | Typical onyx work |
|---|---|---|
| Riverside (92501 to 92509) | Riverside | Backlit islands, bar fronts |
| Moreno Valley countertops | Riverside | Feature walls |
| Corona countertops | Riverside | Home bars, waterfalls |
| Jurupa Valley countertops | Riverside | Accent panels |
| Norco countertops | Riverside | Bar tops, surrounds |
| Eastvale countertops | Riverside | New-build islands |
| Perris countertops | Riverside | Reception desks |
| Colton countertops | San Bernardino | Commercial millwork |
| Grand Terrace countertops | San Bernardino | Powder rooms |
| Redlands countertops | San Bernardino | Feature work |
| Fontana countertops | San Bernardino | Bars and lobbies |
10
Other Materials We Fabricate
If onyx is not the fit, we also install granite countertops, quartz countertops, quartzite countertops, travertine countertops, limestone countertops, soapstone countertops, slate countertops, porcelain countertops and recycled glass countertops.
Questions
Frequently Asked Questions
Or call us on (951) 589-3336. Calls only — we do not receive text messages.
Is the onyx I am being quoted real onyx?
Probably not, and you should ask in writing. True onyx is chalcedony at Mohs 6.5 to 7. Most material sold as onyx is calcite "onyx marble" or "Mexican onyx," which is softer, porous and acid sensitive.
Can I use onyx as a kitchen countertop in Riverside?
Not for the working run. Use it on an island face, a bar front, a vanity or a feature wall, and put a harder surface where the knives and the sink are.
Does onyx have to be backlit?
No, but it is the main reason to choose it. The stone is translucent with a vitreous to silky luster, so a lit slab reads shimmering and semi-translucent instead of flat.
How is the light installed behind the slab?
Standard shop practice is an even LED panel behind the stone with a small air gap so individual diodes do not show. Trade practice, not a published spec, so we mock it up on your slab.
How often does onyx need sealing?
Natural stone generally goes five to ten years between oleophobic impregnator treatments. Onyx in a wet or high-use spot needs a shorter interval.
Do you serve my ZIP code?
We cover 92501 through 92509 plus Corona, Eastvale, Norco, Jurupa Valley, Perris and Moreno Valley, and Colton, Grand Terrace, Redlands and Fontana across the county line.
Services
Countertop services we offer
- Kitchen Countertop Installation
- Bathroom Vanity Tops
- Countertop Replacement
- Countertop Repair
- Custom Fabrication
- Refinishing & Resurfacing
- Sealing & Polishing
- Outdoor Kitchen Countertops
- Commercial Countertops
- All services
Compare
Other surfaces we fabricate
Granite
Heat-tolerant natural stone, the widest slab selection locally.
Quartz
Engineered, non-porous, never needs sealing. Indoors only.
Quartzite
Harder than granite with marble-like movement.
Marble
Classic veining, acid sensitive, superb on vanities.
- Granite
- Quartzite
- Quartz
- Marble
- Soapstone
- Slate
- Travertine
- Limestone
- Butcher Block
- Wood
- Concrete
- Porcelain
- Ceramic Tile
- Stainless Steel
- Copper
- Recycled Glass
- Laminate
- All materials
Services
What we can do with it
- Kitchen Countertop Installation
- Bathroom Vanity Tops
- Countertop Replacement
- Countertop Repair
- Custom Fabrication
- Refinishing & Resurfacing
- Sealing & Polishing
- Outdoor Kitchen Countertops
- Commercial Countertops
- All services
Service areas
Cities we cover
Free quote
Get a Free Written Quote
If you want a surface people stop and look at, onyx does it better than anything else we cut. Bring us the room and we will tell you which stone you are actually being offered, and where it will hold up. Riverside Custom Countertops is licensed and insured, and quotes are written and free. Call (951) 589-3336 or visit 6550 Van Buren Blvd, 1st Floor Ste D, Riverside, CA 92503. ---
- Same business day response, Mon–Sat 7am–6pm.
- No obligation — templating and the written quote are free.
- You speak to the fabricator, not a call centre.
Request your quote
Name, number, and what you need.
Or call (951) 589-3336 — calls only, we don't receive text messages.
Thanks, we have your request.
We reply the same business day, Monday through Saturday. For same-day scheduling call (951) 589-3336.