Often, homeowners find that the landscape rocks around their home just aren’t dark enough.
They either demand a concrete, black appearance with no blemishes or tedious hours of scrubbing to remove moss and algae.
Quite simply, homeowners can apply a sealant, fabric dye, food coloring, or acid stain to the rock.
Staining rock is an inexpensive way to drastically change the look of your rock and will allow you to match the color with your home’s concrete and surrounding.
This type of staining is available in solid colors and mixed shades for more realistic-looking stains.
Can stones be dyed?
Dyes are chemicals mixed together to produce other colors.
They can be mixed with solvents to make paints, resins, and the like or combined with a base to form mordants such as alum.
Stones are tough and endure exposure to air and water and have limited permeability. This is why they appear to be unlikely candidates for dyeing projects.
In fact, studies show that natural stone pumice can be used as an adsorbent for filtering textile dye from a solution mixture.
Phenolic dyes such as those for brick red that rely on the coloring agent’s ability to permeate can easily be used with porous rocks.
Stones and minerals take on their color for a variety of reasons.
This blog post about lightening of natural stone identifies humidity, temperature and UV radiation as factors that cause the surface of natural stone to change over time in the presence of an oxidizing agent, causing them to become darker.
Cementitious dyes and stains such as those used for cement-based flooring impart a color. Stones take on the color of the stain used to make them.
Lighter shades of stones have been artificially induced in several ways.
By using ammonia and sandblasting technology, a marble-like stone can be produced that is lighter than the stone it copies.
Best way to make landscape rocks look darker
Bare rock needs a sealant to hold the desired dark color. As paraffin oil in the sealant sets, the rock gets wetter and darker.
A sealant also protects the rock from moisture and resulting erosion.
However, air can be trapped and be prevented from escaping during cold weather.
This can result in formation of cracks on your rock and may not be ideal for pavers and pathways.
Waterproofing sealant can also be mixed with other products, such as acrylic paint, to achieve different shades of color.
2. Fabric dye or food coloring
Fabric dye or food coloring can also be applied to the rock.
Coffee grounds, for example, provide large quantities of sediment readily available for staining.
Food coloring produces different shades of color which matches the natural sedimentary structure of rocks.
Water-based or acid stain can be applied to rocks instead of using sealant.
Acids are used in the stain to enable it to tone the rock.
This method is recommended if you have a specific color in mind, because you can find a wide range of colored stains from your local hardware.