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Ten Most Common Type of Rocks You Can Find In Rivers

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The term “river rock” describes a variety of rocks that have been worn smooth by the constant movement of water. These rocks can be sedimentary, igneous, or metamorphic, reflecting the diverse geology of the river’s path. For example, rivers flowing through volcanic areas carry igneous rocks like basalt and granite. Sedimentary rocks like limestone, dolomite, and siltstone, often formed in or near water, are common river finds. Even metamorphic rocks, such as marble and schist, can be discovered in rivers, their forms sculpted by the water’s flow.

Granite, basalt, schist, limestone, shale, Jasper, agates, white or pink feldspar, and clear quartz are common in rivers. Petrified wood is also found in rivers or sticking out of riverbanks. A river continuously erodes its banks, freeing many rock types for later discovery downstream.

Rocks and stones that tumble into a river can become surprisingly well-traveled. The heavier they are, the less distance they’ll cover before the current deposits them in shallower spots like gravel bars. This mix of transported rocks, minerals, and even bits of plants forms what we call sediment. The river carries this sediment, eventually dropping it off to create new features like river deltas or piles at the bottom of waterfalls.

Most Common Rocks You Can Find in Rivers
Most Common Rocks You Can Find in Rivers

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Most Common Rocks You Can Find in Rivers

Rivers are often great places for rockhounding. There you can find a lot of beautiful rare rocks. Let’s look at the ten most common rocks you can find in rivers in the sections below.


Granite is a common type of rock found on the banks of rivers and in river beds. It is an igneous rock that forms from lava flows and often contains amphibole, quartz, or mica.

Granite varies widely in color from purple to white, black, gray, and green, and is the most familiar kind of igneous rock to many people.


Basalt is typically dark grey or black due to high augite or pyroxene content and has a range of shading. It is an igneous rock formed from ancient lava flows.

The Columbia River Basalts consists of seven formations: Steens, Imnaha, Grande Ronde, Picture Gorge, Prineville, Wanapum, and Saddle Mountains. It is found mainly in eastern Oregon, Washington, western Idaho, and northern Nevada.

Some basalts contain gemstones like corundum, zircon, and garnets. Raw Oregon Sunstones are found in basalt.


Schist is any medium to coarse-grained metamorphic rock formed from shale or mudstone and is often interleaved with feldspar and quartz.

It is usually named for other rocks found within it, such as garnet schist, tourmaline schist, or mica schist. It is typically gray but can have a banded, ribbed, or striped appearance. Schist is a host rock for several types of gemstones such as sapphire, kyanite, garnet, chrysoberyl ruby, and iolite.

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Most limestone is due to marine deposits, but it also forms in rivers and lakes on land. Rivers flowing through limestone or underneath it often create spectacular caves and rock formations.

It consists of more than 50% calcium carbonate from the remains of countless marine animals that lived millions of years ago and is easily eroded by water.

Limestone is popular with fossil hunters because it contains so many fossil deposits. It can also have larger crystals of calcite and calcite-filled geodes.

Calcite can be clear, white, gray, yellow, blue, orange, violet, brown, or black. The river that flows through the Blue Spring Caverns in Indiana is the longest underground river in the United States.


Shale is a fine-grained sedimentary rock that forms from silt, and clay-sized mineral particles commonly referred to as mud. It consists of many thin layers and splits easily into thin pieces along the laminations. 

The color of shale depends on the presence of specific materials such as iron or organic substances. It is often black and grey but can be red-brown or yellow if deposited in oxygen-rich environments containing iron.

Shale is typically deposited in slow-moving water and is usually deposited in river deltas or flood plains.


Ordinary Jasper is a dense, opaque rock with a uniform red color. However, it can occur in yellow, brown, or dark green.

Its appeal lies in its attractive patterns and color formations Morrisonite is a multicolored jasper from the Owyhee River gorge in Oregon. Jasper can be found in the Nehalem River’s gravel bars and the riverbed of the Clackamas River in Oregon.

A variety of gem-quality Jaspers may be found on the gravel beds along the Willamette River banks from Portland to Eugene. Large boulders of various colors of Jasper can be found in Eel River at Hearst and north of Potter Valley, both in Mendocino County in California.

TIP: Jasper rocks are among the most sought-after stones by rockhounds worldwide. These beautiful rocks can be found in many locations in the United States. Find out more in the article below:
4 Best Locations for Finding Jasper Rocks Near Me (USA)


There are many different kinds of agate, a form of chalcedony characterized by a waxy luster and banding. Carnelian agate is the name given to chalcedony, which is translucent orange-red or brown. Rockhounds around America prize Montana agate for its designs’ beauty and hardness.

When river hunting for agates, look for areas where the water has exposed low gravel bars. Lake Superior agates have been found in deposits in the Mississippi River.

These agates were ripped from billion-year-old lava flows in Lake Superior’s bed by glaciers and traveled down the river to Natchez. Lake Superior agate is well known for its rich red, orange, and yellow coloring.

A five-acre area along the Calapooia River in Linn County, Oregon, is famous for a stunning lavender agate known as Holly Blue. Montana agates occur along the entire length of the Yellowstone River.

Montana Moss agate is transparent to translucent chalcedony with a white, grey, yellowish, or reddish-brown base color and gets its name from black dendritic or mossy inclusions.


Feldspar is the name of a group of closely related anhydrous minerals containing aluminum and silica and one or more basic elements such as potassium, sodium, or calcium.

It is often found in rivers’ igneous, metamorphic, and sedimentary rock. Labradorite is a lovely iridescent feldspar that shimmers with colors of blue, green, red, orange, and yellow. This is called labradorescence. 

Gem-quality feldspar is colorless and glass-clear, but these are rare.  Pink, grey, and white are much more common. “Sunstone” is the name of a type of feldspar that has a brilliant pink to reddish metallic glitter or shimmer.

Potassium feldspar and calcium and sodium feldspars produce gem-quality stones. Amazonite, moonstone, and orthoclase are well-known feldspar gems.

TIP: Cleavage is one of the vital properties of minerals needed for mineral identification. Check out the complete guide on testing mineral’s cleavage in the article below:
Complete Guide: Testing Cleavage of a Mineral like a PRO


Quartz Crystal
Quartz Crystal

When quartz-bearing rocks are eroded, quartz grains are concentrated in the soil and rivers. White sand typically found in riverbeds is mainly composed of quartz.

Unusual blue quartz is located in Virginia and has a pearly or waxy luster. The color of blue quartz ranges from light sky blue to dark grayish-blue. Quartz comes in many different colors, such as pink (rose quartz), purple (amethyst), clear, white, yellow, black, green, and red.

Gravels along the Robinson River in Madison County contain blue quartz. In Greene County, blue quartz can be found in the stream gravel of Middle River, while in Amherst County, it is in the stream gravel beds of the Pedlar and Buffalo Rivers.

The Tye River in Nelson County also has blue quartz with white quartz. In Texas, blue quartz can be found in the Llano River, along with many other rocks like clear quartz, topaz, agate, fluorite, garnet, and smoky quartz.

Petrified Wood

Petrified wood comes in different kinds, such as silicified wood, in which the wood has been replaced by silica, or opalized wood, where the wood has been replaced by opal. In both cases, the original wood grain is usually preserved and clearly visible in the rock.

TIP: Do you know how valuable petrified wood can be? There are a lot of different kinds of petrified wood, and they can have different values. Find out more about the value of petrified wood in the article below:
Crucial Factors of Petrified Wood Value: What’s the Worth?

Tips For Finding Rocks in Rivers

A river grinds at the bedrock, carrying sand and other rocks downstream when it flows over it. Strong currents create hydraulic action that causes the softer rock to erode and dissolve.

Gemstones and gem-bearing rocks carried by rivers are called alluvial deposits and can be transported miles downriver. Keep an eye out for gravel bars in shallow parts of the river, especially where it bends.

Riverbanks, basins, and old riverbeds are ideal places to go rockhounding as the rocks are usually clearly visible and washed clean by the water.

Learn about local rivers and their geology in your area by consulting rockhounding guides, websites, and natural history museums. Look for recently eroded cliffs and banks along rivers for fresh pickings.

TIP: You already know what rocks can be found in rivers, so it is time to try to find some. Do you know what tools you need to take with you? Check out this complete guide with all the tools you need for rockhounding:
The Complete Guide: All Tools You Need for Rockhounding