Arizona holds billions of years of rock history and you’ve got quite an inquisitive adventure ahead of you when you find one.
From silt to granite to volcanic rocks, the Grand Canyon State really rocks.
Types of Rocks Found In Arizona: A Guide
The information provided in this article by YesDirt.com is for informational purposes and is subject to change. Laws are updated. Accessibility guidelines and restrictions change. Be sure to confirm the land status and collection rules before you travel to an unfamiliar location or collect any material.
Rock Rules in Arizona
You’ve got to know the rules of the land before you pack away the unique rock you find along your path.
The Bureau of Land Management has clear lines of what you can and cannot do when rockhounding in Arizona.
You can collect a “reasonable amount”, which equals about 25 pounds per day, or 250 pounds per year, and you cannot sell these rocks.
They must be for personal use only. To remove any rock, you can use any heavy equipment. Metal detectors are allowed.
The state parks are much more rigid.
It is illegal to take a rock from an Arizona State Park.
While it doesn’t seem like a big deal for you to take a rock, imagine if every one of the 10 million tours in Arizona each year took a rock.
There wouldn’t be many rocks left.
Now let’s dive into the most common rocks you’ll see while wandering around Arizona.
Where to find it: Statewide, with a strong presence in eastern Arizona
Volcanic rock is easy to spot and hard to wrap your head around.
When you pick up a rock, you’re really holding what was once lava flowing from a volcano.
Pretty cool, eh?
You can even visit the Sunset Crater Volcano in northern Arizona.
These rocks are so finely ground you can’t see any of the mineral makeup with the naked eye.
We talked about basalt elsewhere in this article, but there are several variations of volcanic rock to be found in Arizona.
Where to find it: Around the Flagstaff area, far east-central Arizona
This is a volcanic rock that is dark with a fine-grained appearance.
It’s used to make statues and cobblestone while also being a building block of construction work. It’s so strong that even the ocean beds are made up of basalt.
It’s generally a dark gray or black color with no crystals or minerals seen by the naked eye.
A less common volcanic rock found in Arizona, felsite, is identified by this light color.
Another name for this rock classification is rhyolite.
To get a general idea of the appearance of these rocks, check out the Superstition Mountains in the Sonoran Desert.
Arizona is home to three volcanic fields, so finding volcanic rock is very easy.
Where to find it: Central Arizona, north of Phoenix down to the southeastern part of the state
These speckled stones will have you “oohing” and “ahhing” as you sort through them.
The banded appearance is formed by high temperatures and high pressure forcing dark and light mineral elements together to form what is called gneissic banding.
These are some of the oldest rocks on earth, some dating back 3.5 billion years.
Where to find it: Most like around the northeast part of Arizona
On the surface, limestone can look like a rather boring rock, but what’s inside makes it so dynamic.
It’s made up of calcium and carbonate and includes fossils or fossil fragments and some shell pieces as well.
Arizona is one of several desert states that have Kaibab Limestone.
To give you an idea of what that is – the rim of the Grand Canyon is Kaibab Limestone.
Many of the cliffs in the northern Arizona region are naturally carved from limestone.
Where to find it: Northeast and central Arizona
The name derives from the structure of the rock, which is made of sand-sized grains of silicate.
They come in colors across the brown spectrum, but can also be found in white, pink, gray, and black.
The reddish-orange smooth canyon walls found throughout the desert are made of sandstone.
This rock looks like waves of color running throughout it.
It’s jaw-dropping and easy to identify.
Pronounced: SHist (no long “I” sound)
Where to find it: Scattered throughout the central and southern part of Arizona
If you’ve seen a decorative rock display in a home or business, it’s likely made partially of schist.
As far as rocks go, they break and crack pretty easily, so they aren’t used much for lending sturdiness to a foundation.
You’ll easily be able to identify particles within this rock and the sparkle of those could be what caught your eye to this rock in the first place.
Several variations of schist exist in Arizona.
We can’t talk about things you’ll find in Arizona without talking about petrified wood.
No, it’s not a rock, but it might look like one at first blush.
There’s a whole national forest in Arizona filled with petrified wood.
This fossil is made of quartz and you can tell it’s legit by holding it up to the desert sun and seeing the sparkle.
This is classified as a semi-precious gemstone and can be made into jewelry and other decorative elements.
If you are in the park, you cannot take any of the petrified wood with you.
Again, only BLM lands allow you to take certain weight limits of things you find in the desert.
In fact, urban Arizona legend says that anyone who takes wood from the park will be cursed.
There is even a display about thieves who tried and shared their tales of misfortune.
While so many rocks have internal structures that make up their identifiers, you can’t always see that with the human eye.
Google Lens is a great app to bring along and you just upload a picture of the rock and then you get help identifying what rock it is.
Check out a rock and mineral club in Arizona to get help to guide you to the best location.
Remember when rockhounding in Arizona – it’s a desert out there.
Think about how much water you’ll need and then double that amount.
The desert is beautiful but unforgiving.
Prepare for extreme heat or cold, depending on the time of year, and know the low humidity is going to zap water from your body.
Good luck, rockhounds.
Arizona Rockhounding Resources
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