River rock looks pretty amazing in the river.
The stones are shiny and the colors are deep.
When you bring the stones home (or use them in the yard), not so much.
In this article, we’ll talk about how to brighten up river rock.
But first, we need to understand why the rocks look so dull as compared to when they are in in the river.
Why Do Rocks Look Different When Wet?
This is an interesting question.
What we see when we look at the stone has to do with the light particles reflecting off the surface.
When the stone is dry and sitting on the ground (or a shelf), the light bouncing off the stones (especially stones that are rough) tends to be irregular and scattered. (source)
When a stone is wet (or oiled), a new surface is created.
Water doesn’t have jagged edges, dents, pock marks, etc.
Thus, the surface area is much more regular and consistent (smooth).
The water/oil also fills in the rough, irregular spots, as a polishing just outright removes it them.
As a result, the light particles bouncing off the surface are also more regular and consistent.
Further, water also apparently helps light penetrate the surface of the stone just a bit before bouncing off, which adds to the color.
Consequently, when the stone is dry (and rough), the colors of the stone won’t seem as rich or deep as they do when the surface is wet or polished.
Ways to Make River Rocks Look Good
Now that we understand why river rocks can look dull (generally due to a rough, irregular surface), we can talk about the ways to brighten them up.
Store River Rocks in Water
One of the easiest (and cheapest) ways to enjoy the beautiful colors of the river rock you’ve collected or displayed around your home is to put it in water.
Place it with plants and water in clear vessels, or use it in a water feature.
Clean The River Rock To Let In More Light When It Is Dry
One of the easiest ways to make river rock look brighter is to clean off all of the accumulated dust, dirt, lichen, or other organic material.
River rock that comes from the river and has been outside in the elements (especially if it has been in your yard) will looks tons better if you get it clean because the light particles can actually reach the surface of the stone.
This is true even of rocks that have been in the water for a long period of time, as sediment and other particles can get get stuck to or grown on the surfaces.
This could be as simple as scrubbing the rocks with a stiff brush and dish soap (or laundry soap) by hand.
If you are looking to wash a lot of rocks, soaking them in a soap and water solution and generally scrubbing at them with a long handled brush, push broom, or foam mop will get most of the muck off.
Some folks like to soak the rocks in a solution of bleach and water, or vinegar and water, after the soap/brushing.
You might want to do this if the rocks you are cleaning are light colored or white, and washing/scrubbing did not remove dark stains.
Or if you have been struggling with mold or algae growing on them.
Just make sure that the soap has been completely washed away, as some dish soaps (or laundry soaps) create poorly with bleach solutions.
Read also: A Beginner’s Guide To Cleaning River Rock
Use a Product To Create an Artificially Smooth Surface
Once the rocks are clean, the best way to help the light bounce off the rocks in a pleasing way is to make the surface smooth.
This can be done with products, such as a high gloss concrete sealer, lacquer, varnish, oil, silicone, polycrylic, polyurethane, Thomsen’s Water seal, car wax, etc.
If you can, spread out your rocks and apply the coating on one side, letting it dry thoroughly.
Then turn the rocks over to apply the product to the other.
If you display your rocks outside (or they make up part of your landscaping), you will have to clean them every now and again, and even re-seal them periodically.
Making the Surface Smoother Before Adding Product
Another thing you could do in addition to cleaning up your rocks is removing as much of the rough surfaces as you can.
This can be done by hand or with the use of a rock tumbler.
Most people choose not to tumble river rock, as it can take weeks to tumble a small number of stones until the stones are smooth enough.
However, it is done.
If you are going to tumble river rock, try and do batches of similar rocks together.
River stones tend to be varied in size, shape, and hardness.
If you put soft rocks in with harder ones, you might find that the soft rocks end up looking worse for wear while the harder ones barely change.
Start with a larger grit and work you way down through finer grits until the rocks look the way you want.
Between each grit change, wash off the rocks and let them dry completely before resuming the tumbling, as the rocks do look different wet versus dry.
It is fairly common in landscaping to just dig out dirty rock and replace it with rock that is clean and free of debris.
But with a little work, you can save yourself a lot of time and money.
Want to know more about collecting rocks from rivers, and cleaning up the rocks in your collection?
Check out our Knowledge Vault for more articles you’ll enjoy.