Cultured Marble vs. Onyx

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There are many choices on the market today for bathroom designs. Materials used in shower surrounds and countertops have expanded to include man-made products such as cultured marble and natural stone products such as onyx. Understanding the care and style of these products can help you decide which one is right for your home.

Cultured Marble Overview

Cultured marble is a resin which is mixed with crushed or ground marble dust. This resin is then poured into a mold and used to form shower wall surrounds and bathroom vanity countertops. The material is fairly low maintenance and seamless, often with integral soap dishes and sinks.

Onyx Overview

Onyx is a type of very fragile marble, a metamorphic stone. Onyx is translucent, meaning it can be seen through if held to the light or lit from behind, and extremely variable in color and pattern. Like other marbles, onyx is available in tiles and slabs for countertops and can be used in shower surrounds or on vanity tops.

Cultured Marble Style and Cost

Cultured marble frequently has a high shine applied to its surface in the form of a gel coat. Shower stalls are free of grout lines and seams, while sinks can be made of the same material in a vanity top. Colors are limited by manufacturer, but are fairly uniform and consistent from piece to piece and within one piece. Like natural marble, cultured marble will have veining and color differences, but this can be controlled during the manufacturing process for a more uniform material.

Cultured marble can cost from $10 a square foot to $35 a square foot for some colors.

Onyx Style and Cost

Onyx is an extremely variable stone, with wild veins and multiple colors. No two pieces of onyx are ever the same, and one slab can include multiple colors. The material is usually ground to a high polish and can be lit from below in vanity tops for a modern look. Onyx is available in a wide range of colors from golds to greens, reds, blues and browns. The tiles will have to be grouted into a shower surround, but are available in sizes from 3/8 inch up to 16 inches in size. Sinks can be undermounted, drop-in or vessel, depending on taste.

Onyx is a more expensive stone with prices ranging from $17 a square foot to $150 a square foot for more exotic materials.

Cultured Marble Care

Cultured marble can be cared for and maintained with a liquid nonabrasive cleaner. Glass cleaners are acceptable for use, as are many other bathroom cleansers. Scratches and dull spots can be repaired with a fresh coat of gel gloss by the homeowner.

Onyx Care

Onyx is a type of marble and should be treated accordingly. It should be sealed on a regular basis in wet areas, and cleaned with a stone cleaner or mild detergent. If possible, onyx should be squeegeed or toweled dry to help prevent staining or etching of the stone.


Sarabeth Asaff

Sarabeth Asaff has worked in and has written about the home improvement industry since 1995. She has written numerous articles on art, interior design and home improvements, specializing in kitchen and bathroom design. A member in good standing with the National Kitchen and Bath Association, Asaff has working knowledge of all areas of home design.