Flash: The Many Different Types of Rocks

Learn more about the rocks you climb
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Learn more about the rocks you climb

This story originally appeared in the July 2015 issue of our print edition.

flash rock type

Photo: Andrew Burr

Rock Type: Granite
Climber: Rob Pizem
Route: Vesteggen (6/5.10b)
Location: Stetind, Norway

“Piz” has an unwavering appetite for big wall new-routing, especially on granite. It’s brought him across the States and throughout the world, and eventually it landed us on the Stetind, the National Mountain of Norway, which was first climbed in 1910. There’s a heavy no-bolting ethic here. Just 2,000 feet of clean, amazing granite. Slab climbing reigns supreme here, although we did find this tasty fist crack high up on the peak.

Crag-side Geology

After 13 years of shooting climbers on stone, I’ve seen a lot of damn rock, and a side effect is that I’ve become a bit of an amateur geologist (and in my former life I was a hydrologist for the USGS). Actual geologists will go on at length about the super-technical, nerdy details, but that’s not what I’m going to do here. You can bust my balls about it if you want, but I’d argue most of that doesn’t affect the average climber. I’m just going to tell you a little bit about how different rock types formed—and how they climb—so you can sound smarter on your next sesh.

There are three basic rock types: igneous (formed when liquid magma cools), sedimentary (formed by the deposition of tiny materials), and metamorphic (formed when rock is squeezed and baked underground).

When an igneous rock forms below ground (an “intrusive”), the slower cooling allows for crystals to form, and it becomes our beloved granite. If that same lava flows at or near the surface of the Earth (“extrusive”), it cools much faster, leaving almost no crystalline structure, but the resulting rhyolite or basalt still make for amazing climbing.

Now, sedimentary. There are numerous classifications of sedimentary rock, but really only three that climbers care about. The first is sandstone. It’s all over the place, from the splitters of the desert Southwest to the backwoods jug-hauls of Kentucky’s hollers. When sand is deposited via a river, it’s considered fluvial (the Red), but when laid down by the wind (sand dunes), it’s Aeolian (Indian Creek). The second is conglomerate, basically river rocks that have been cemented together (think Utah’s Maple Canyon). The third type is limestone (France’s Céüse is the finest example). It’s made from tiny shells and sea creatures that died and stacked up at the bottom of shallow oceans. And it climbs so nice!

When an igneous or sedimentary rock is exposed to heat and pressure, you get what we call metamorphic rocks. Sandstone often turns into quartzite, and limestone can become marble. Granite will turn into gneiss. You’ll see bands of these rock types in the alpine or variations of them in Colorado’s Black Canyon or New Hampshire’s Rumney. Read on for details on the quality of climbing each rock type presents.

flash rock type

Photo: Andrew Burr

Rock type: Limestone
Climber: Cody Roth
Route: Incantesimo (8a/5.13b)
Location: Dolomites, Italy

Cody Roth left Albuquerque, New Mexico, when he was just 18 to climb. He was in and out of the World Cup climbing scene for the next 10 years as he based himself out of Austria (illegally!). We found this wicked limestone cave just above the sleepy town of Covolo. These places are a dime a dozen in Italy—and this was tufa wrestling at its finest.

flash rock type

Photo: Andrew Burr

Rock type: Limestone
Climber: Ari Menitove
Route: Ctuluh (6c+/5.11c)
Location: Verdon Gorge, France

My good friend and fellow Utahn Ari Menitove is a trad climber at heart, so he adapted quickly to the bold and runout style of climbing that the Verdon often dishes out. These world-class, 1,000-foot walls of really hard but aesthetic limestone present a climbing style so good we called it “Tech 9.”

flash rock type

Photo: Andrew Burr

Rock type: Sandstone
Climber: Brittany Griffith
Route: Desert Shield (5.12c)
Location: Indian Creek, Utah

Desert climber extraordinaire Brittany Griffith (who also answers to the lovely nicknames “BAG” and “Gypsy Queen”) is one of the most well-rounded and well-traveled climbers in the world. So it says something that she continually returns to this sandstone splitter crack mecca. She can’t get enough of the unrefined, blue-collar, slugfest style of climbing. 

flash rock type

Photo: Andrew Burr

Rock type: Basalt
Climber: Andrew Marshall
Route: Hexentric (5.7)
Location: Sonora Pass, California

Andrew Marshall is the muscle behind Patagonia’s distribution center in Reno—and a skier at heart. We snuck away to this little-known area tucked in a remote corner of the Sierra not long ago. It’s known for its Jailhouse Rock–style of overhanging climbing, but it’s also one of the rare places where you can climb across the diameter of volcanic basalt columns stacked on top of one another, rather than climb seams along their length. It’s technical and somewhat terrifying.

flash rock type

Photo: Andrew Burr

 Rock type: Quartzite
Climber: Mayan Smith-Gobat
Route: Lord of the Rings (31/5.13d)
Location: Mount Arapiles, Australia

Have you seen the guns on this gal? She knows how to rock climb. Mayan may be from New Zealand, but she loves the rock in Australia just the same. Arapiles is very historic and one of the world’s best climbing areas. It’s amazing how flat the surrounding Outback is around this small mountain. The quartzite delivers small holds—very fingery. Bring a new pair of shoes.