How to Lay an Onyx Slab

Cutting

• Onyx slabs are available in a variety of shapes and sizes. Many suppliers can customize your order and cut the slab according to your requirements. Others may sell standard onyx slabs, and in such cases, it's your job to cut the slab to your measurements without chipping it. The edges of the countertop can be square, curved, angled, beveled or eased. If you're cutting the slab yourself, and this is your first project with onyx, try a simple square edge for best results. A wet saw that uses water-cooled diamond blade is a good tool to cut onyx slabs cleanly and safely.

Lights

• The translucent texture and vivid colors and veins of onyx slabs can be further enhanced by backlighting the surface of the slab. Use 1/2-inch light panels or LED sheets that provide uniform lighting with no hot or cold spots. You may also manipulate the colors of the onyx slab by reflecting the light on your countertops, instead of focusing it directly.

Laying

• The slabs are usually layed over a countertop support frame that has cabinets in the bottom. You may require some professional help to do the final priming and fitting. Remember that onyx is a delicate stone, and it may not be possible to remove the slab and redo it without breaking or chipping it.

Sealing

• Sealing the onyx slab helps prevent scratches, as well as stopping water or acids from foods from ruining the countertop's surface. Before sealing the onyx countertop, clean it with warm water and a special onyx cleaner. Most countertop cleaners may be too acidic for onyx. Use natural cleaning products with a neutral pH and a soft cloth to clean the onyx slab. The website Granite Insider recommends a fluorocarbon alphatic resin sealer because it doesn't evaporate or go through any type of natural deterioration like regular silicon sealers.