White Onyx

 Our Most Popular Grout-Free Shower Color

Bright, timeless, and highly versatile, White Onyx has been installed in bathrooms throughout the Northeast for decades. Its clean white background and signature bright white swirl pattern make it a natural fit for virtually any design style. 

  • Available in gloss or matte finishes.



  • Proudly manufactured in Connecticut since 1977. 


  • One of Syn-Mar's proprietary colors. 

White Onyx Design Gallery

Explore how White Onyx elevates residential spaces. Because all of our colors are hand-cast, each panel will have a unique vein structure and placement, ensuring your grout-free shower system is completely one-of-a-kind.

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Why Homeowners Love White Onyx

Works With Virtually Any Design Style

Whether you're designing a modern, traditional, coastal, farmhouse, or transitional space, White Onyx provides a neutral foundation that complements almost any color palette.

Modern bathroom with wood vanity, mirror, and glass shower with white textured tile shower wall

Warm or Cool — You Decide

Think of White Onyx as a blank canvas that adapts to the design choices around it. The surrounding finishes help shape the overall feel of the room:

  • Cool gray cabinetry creates a crisp, contemporary look.

  • Warm wood tones create a softer, inviting feel.


  • Black fixtures create bold contrast.


  • Brushed nickel creates a timeless appearance.

What Makes White Onyx Unique?

Stone countertop fabrication shop with workers polishing a large granite slab

A Unique Translucent Appearance

Unlike many Syn-Mar colors, White Onyx retains a degree of translucency. If illuminated from behind, light can pass through portions of the material, creating depth and visual interest within the surface.

Installation Considerations

Because of this translucent characteristic, proper wall preparation is important during installation. We highly recommend priming the wallboard with white primer prior to installation to prevent underlying colors, seams, or imperfections from creating visible shadows. All of Syn-Mar’s Onyx and Carrara series feature this same translucency and require priming the wallboard with white primer before the walls are installed.

How White Onyx Is Made

Manufactured in Connecticut Since 1977

Syn-Mar engineered stone is produced using approximately 25% polyester resin and 75% crushed stone particles. The materials are carefully blended with pigments and a catalyst before being cast into molds and finished by hand. Every White Onyx shower system is manufactured in our Connecticut facility. 


White Onyx is our most popular color. On most days, you'll find White Onyx products somewhere on our manufacturing floor, being cast, finished, inspected, or prepared for shipment throughout the Northeast.

White Onyx Showroom Spotlight

White tiled shower stall with built-in shelves, showerhead, grab bars, and a handheld sprayer.

Featured Display Details:

  • Mid-height threshold shower base


  • 3" tall x 4" wide threshold


  • Corner trim


  • Two corner shelves


  • Matte finish

Frequently Asked Questions

  • Is White Onyx pure white?

    White Onyx features a white background with a bright white swirl.

  • Does White Onyx have variation in color?

    All Syn-Mar colors are made with precise formulas and processes to ensure color consistency. However, all of our colors are hand-cast and will have unique vein structure and placement. No two panels are ever alike.

  • Is White Onyx available in matte and gloss?

    Yes, White Onyx is available in both matte or gloss finishes.

  • What products are available in White Onyx?

    White Onyx is available in shower walls, custom shower bases, soap and shampoo accessories, and seamless vanity tops.

  • Why does White Onyx require white primer behind the wall panels?

    White Onyx is slightly translucent, which is why we recommend applying white primer to your wallboard before installing your White Onyx walls.

Why Choose Syn-Mar?

Syn-Mar Products is a third-generation, family-owned manufacturer of grout-free shower systems, custom shower bases, and seamless vanity tops. Since 1977, we've manufactured engineered stone products in Connecticut and proudly supplied dealer partners throughout the Northeast.


We operate strictly as a direct manufacturer, not a remodeler or installer. For our B2B plumbing wholesalers and showroom partners, this means we sell direct to you—unlike competitors who rely on middle-man distribution companies. We stand behind our high-quality craftsmanship with a 5-year warranty.

Ready for a Beautiful, Grout-Free Bathroom?

Syn-Mar products are supplied exclusively through our trusted network of B2B dealer partners. If you are a homeowner looking to upgrade your space with White Onyx, connect with an authorized dealer today.