Favorite Obscure Rock Formation to Climb?

Spider Savage wrote: Schist. Now there's a rock that is interesting to climb. Flaky. Melts in your hands.

Really? Evidently you've never experienced good schist. That can be some of the most rewarding rock on which to climb.

Volcanic Tuff is the most interesting rock ever! Lots of variety, though its sadly scarce. Here are two polar examples,

Enchanted Tower New Mexico, steep & juggy

and Smith Rock Oregon, thin & technical

Boulder Canyon's Fin of Krappe:

It awaits!

think the technical term is conglomerate basalt held together by moss:

Great desert mountaineering. Stnd route is 5.fun.

One giant heap of choss, with good fun in between.

Spider Savage wrote:Porphyry is cool. Some of that in the South Tyrol region of Italy. Red with white spots. Also like granite.

Porphry is actually a term given to any igneous rock with obvious large crystals within a matrix of fine-grained groundmass.

Spider Savage wrote:Tuft is nice an hard with solution pockets but very abrasive. Some of that at Enchanted Tower in New Mexico and up near Bishop in the Owens Gorge.

It's tuff, not tuft. And, those aren't solution pockets, they are gas pockets.

I found a big boulder almost completely made of Milky Quartz with a bunch of mica thrown in to make it loose. We did some top roping because the landing was atrocious. It was like climbing on slippery, sharp and loose glass.

This isn't a very good picture, but the right side of the quartz boulder is about 15 feet tall, overhanging, and sharper than a Menses meeting.

Then there is this obscure type of formation: