Bespoke Onyx Bathtub Production for Custom Projects
GLMStone has over 20 years of stone fabrication experience, producing custom onyx bathtubs for designers, contractors, hotels and importers. Our 10,000+㎡ factory combines 5-axis CNC machining with experienced stone craftsmen for rough carving, profiling, polishing and final detailing. Critical dimensions can be controlled within ±0.5 mm where required, followed by dimensional, surface, drainage and structural checks before packing.
For custom onyx bathtub projects, we confirm the actual block, vein direction and translucency under normal and backlight conditions before cutting. Tub size, wall thickness, drain position, overflow and lighting method are fixed in the approved drawing. After rough carving, newly exposed fissures and weak areas are checked again before final machining. Finished weight, crate size, water test and backlight test are also confirmed before shipment.
Onyx Bathtubs in Natural Colors, Shapes & Backlit Designs
Explore solid onyx bathtubs in pink, green, white, black and blue stone. Tub shape, wall thickness, drain position and backlighting details can be adjusted from your approved drawing.
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Solid Onyx BathtubCarved from one stone block for cleaner curves, fewer joints and stronger visual continuity.
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Pink Onyx BathtubSoft pink and amber bands work well in luxury suites, villas and statement bathrooms.
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Green Onyx BathtubLayered green tones and translucent veins create a stronger natural effect under backlighting.
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White Onyx BathtubLight cream and white crystal areas suit quiet, bright bathrooms and spa interiors.
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Black Onyx BathtubDark stone with lighter veins gives high-contrast bathrooms a more architectural appearance.
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Blue Onyx BathtubBlue-grey crystal movement suits bespoke interiors where the bathtub becomes the main visual feature.
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Backlit Onyx BathtubWall thickness and light-facing areas are reviewed before machining for a more controlled lighting effect.
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Oval Onyx BathtubRounded sides and softened rims suit freestanding layouts with more circulation space around the tub.
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Rectangular Onyx BathtubStraighter walls fit modern hotel bathrooms, large master suites and more structured interior layouts.
What Makes Natural Onyx Different for Bathtub Design
Onyx is selected for more than its color. Its natural translucency, layered mineral bands and solid-block form create effects that are difficult to reproduce. At GLMStone, we select the block around its actual vein movement and light transmission, then match the carving and finish to the approved bathtub design.
One-piece carving removes visible panel joints and keeps the bathtub form visually continuous.
Natural layers, clouds and crystal areas give every finished bathtub a different visual pattern.
The stone absorbs and retains heat gradually, giving the tub a heavier, more substantial bathing feel.
Selected onyx can transmit light through thinner sections, creating a soft backlit glow.
Fissure Check and Concealed Reinforcement After Rough Carving
After rough CNC carving, our team checks the exposed rim, base and drain area again for hidden fissures that were not visible on the original block. Suspicious areas can be reviewed with ultrasonic testing before final machining. Where extra support is needed, we cut concealed kerfs on the underside and fit them with fiberglass rods or mesh using stone epoxy. Visible fissures are cleaned and repaired separately before polishing.
Wall Thickness Control During 5-Axis CNC Machining
Wall thickness is measured at the rim, side wall, base transition and other critical points during our CNC machining process. Where the drawing requires tighter control, key dimensions can be held within ±0.5 mm. After polishing, our QC team fills the tub for a 48-hour water-tightness test. The selected LED source is then set under or around the tub to check bright spots, dark areas and the actual vein transmission before packing.
More Onyx Choices, Better Control from Block to Finished Tub
Our 10,000+㎡ stone warehouse gives you more onyx options in color, vein movement, translucency and block size, making it easier to select pieces within a closer visual range for project orders. After the block is approved, 5-axis CNC handles the main hollowing, bowl profile, curved rim and drain area, followed by thickness checks, polishing and hand finishing.
Onyx Bathtub Support for Design, Hospitality & Project Delivery
An onyx bathtub may pass through designers, procurement teams, contractors and installers before it reaches site. Each group needs different drawings, inspection records and delivery details.
You can receive the finished tub weight, crate dimensions, base footprint and drain centerline as part of the dispatch information. This gives your site team the actual numbers for access and lifting preparation.
Weak underside areas may use concealed kerfs, fiberglass rodding and stone epoxy when the structure needs reinforcement. Lifting direction and strap positions can also be marked on the crate.
We fill the finished tub and keep the water level for 48 hours to check leakage. Drain center, outlet diameter and overflow position are matched to your specified fittings on the shop drawing. Rough carving, polishing, water test and packing photos can be sent as separate production records, especially when one hotel order includes several tubs or room numbers.
The rim, base and projecting parts are protected with shape-fitted high-density foam, then fixed inside a reinforced export crate. Crate size and shipping weight are recorded after packing.
If your showroom model uses backlighting, the lighting cavity, cable route and base clearance are left in the production drawing during CNC work. These details should not be added after the tub arrives.
Onyx can look very different once light passes through it. We photograph the selected block under normal light and backlight first, so you can check the vein direction, darker bands and color areas on the actual stone.
Your CAD drawing is then used for the tub profile, wall thickness and drain position. If the design needs backlighting, we test the finished piece again after polishing using your specified LED color temperature. A 360° video can be recorded at this stage.
From Onyx Block to Finished Bathtub in Four Controlled Steps
Each onyx bathtub follows a controlled process from block approval to final testing. Stone condition, CNC machining, weak-area reinforcement and finished performance are checked at different stages before packing.
Actual block color, vein direction and translucency are reviewed first. Visible fissures and questionable areas are marked before the carving layout is fixed.
The approved CAD file guides rough hollowing, bowl profiling, rim shaping and drain machining, with critical dimensions checked during CNC processing.
Edges and curved transitions are hand-finished after machining. Weak underside sections can use fiberglass rodding, mesh and stone epoxy where extra support is needed.
The tub is fixed with high-density foam around the rim, base and weak edges, then packed in a reinforced wooden or metal crate with lifting and handling marks.
Confirm the Main Details Before Your Onyx Bathtub Goes into Production
Stone block, finished size, plumbing position and backlighting details are checked before carving. Non-standard shapes and dimensions can be developed from your approved drawing.
- Onyx Colors
- Bathtub Size
- Drain & Overflow
- Backlight & Finish
Review the Actual Block Before Cutting
Standard Reference Sizes + Custom Dimensions
Fix Plumbing Positions in the Shop Drawing
Plan the Lighting Effect Before Final Polishing
Onyx is usually chosen when translucency and backlighting are part of the bathroom design. Marble offers more familiar veining and is generally easier to source in large blocks, while granite is harder and more resistant to scratching. Onyx needs more attention to natural fissures, wall thickness and handling, but its light transmission and layered color bands give it a visual effect that marble and granite cannot normally provide.
No. The actual stone decides the result.
Some onyx blocks light up clearly, while dark bands or dense crystal areas stay much darker.
It can, especially when a fissure sits near the rim, drain area or another thin section. Some weak bands are visible before cutting, but others only show after rough carving.
A one-piece onyx bathtub is heavy, but length alone cannot tell you the final weight. Bowl depth and the amount of stone removed during carving also make a large difference.
Use warm water, mild soap and a soft cloth for normal cleaning. Acid cleaners and rough pads should not be used on onyx.Bath oil, colored products or soap residue are better rinsed off early instead of staying on the stone surface.
We normally start with the block. Its size, usable carving area and color can change the material cost a lot.A deeper bowl or curved profile means more machining. Backlight preparation, reinforcement, special drain work and export packing are added according to your drawing.
Explore More Natural Stone Bathtubs & Basins
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CNC shaped and hand finished forrounded, oval and sculptural bathtubdesigns.
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Pink Marble BathtubNatural pink marble with clear color
movement and veins. -
Carrara Marble BathtubCarrara marble with white-grey tones,suitable for oval, round and simplemodern bathtub forms.
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Freestanding Marble BathtubOval and soft curved freestanding tubsfor villas, hotels and residentialbathroom projects.