UKC

I have been wondering how a person can tell the difference between soft and hard sandstone (e.g. for registering a crag) without being a seasoned geologist.

I live in Newcastle-upon-Tyne, and do most of my climbing in Northumberland. Most of it is of two types of sandstone, Fluvial or Fell. I thought that maybe one of these was soft and the other, hard. I was wrong. Apparently there is only one crag in Northumberland which is registered as soft sandstone on this site. I have been to Corby's Crag once and I can't see how it is much different to all the other crags surrounding it. After my brief research, I believe it has been mis-registered.

I understand that a lot of sandstone in the south-east is soft, and that leading is forbidden. Presumably this is because the soft rock is easily damaged by people falling on gear. Leading at Corby's is not an issue as far as I can see (although it is apparently friable in some places, the rock is generally sound), suggesting it isn't soft sandstone. The guidebook states that it has been mostly damaged by top-roping (abseilers), due to it's accessibility. However, we did (unintentionally) chip one of the holds (sorry), and not because of gear.

In reply to Tommy Alsop:

Well, yes. And also because the rock won't hold your gear and you'll deck out...

In reply to Tommy Alsop:

I think you can't take what the crag has been registered as on this site as definitive.

The stuff in the SE is a lot softer, and there are sandstones that are a lot harder than that found in Northumberland. It's something to do with the the material that minds the sand grains together. One of the geologists on here will be able to answer a lot better than me.

In reply to Tommy Alsop: All sand stone is not particularly hard and will erode easily. It is a relative term - if you brush it with your hand and you remove sand then its soft. If it doesn't then its hard. But it will only take ropes running over it repeatedly in one area to erode... if it really is soft you'd know it pretty quickly... As for accidentally chipping holds off, any sand stone is friable and requires care - it should come with a government health warning

In reply to mike kann:

AFAIK grit is just a course-grained sandstone, or is there a geologist in the house who can tell us otherwise?

My impression is that Torridonian sandstone is pretty hard, although I'd admit I've only walked/scrambled in the area, not climbed.

In reply to Stefan Lloyd: That is correct, although I believe it has been modified in someway. With regards to its softness, what I meant was its relative hardness to other stones - eg granite, Gabbro etc. - generally its the sofest stone you would climb on. Don't get me wrong though, I love the stuff

In reply to Stefan Lloyd: Yep, grit is effectively a coarse grained sandstone. Generally speaking, its the cement that holds the grains together as well the grain sizes and the degree of sorting that determines its strength

In reply to Tommy Alsop:

I propose a scale along the lines of the Mohs scale of relative hardness in minerals

Fell sandstone hard
Font - variable
SE - quite soft
Nesscliffe soft
Kinver (midlands) very soft

call it the FSNEK scale.

In reply to Yorkspud: Go on then - whats FSNEK mean then?

In reply to mike kann: Take the first letter from each component of the the scale he's developed

In reply to Tommy Alsop:
I'm not a geologist but I don't think geology has a distinction I think this is a subjective climber thing.

In reply to Big Steve: Where did the E spring from and the seconf F go to?

In reply to mike kann: evolution I think

In reply to CurlyStevo: Of course there is a geological distinction. The composition of different sandstones defines them. Why do you think it is totally safe to place gear on Table Mountain, but not at Bowles? Is that subjective?