This week we pushed down to about 70m depth at Vurley. The current end is a boulder choke with a stream below. I noticed a very conspicuous red rock in the choke so brought it out.

Rock in situ.



It is very hard and shiny on the outside.



I tried to cut a bit off the end with an angle grinder but it was too hard. Used a flat chisel instead.



Magnified.



It looks a bit like a red brick. I was wondering about Old Red Sandstone but it is not like the ORS we had in The Silo in Reservoir Hole. This was transported into The Silo through an ancient stream sink in the gorge floor and would have been carried down from the pericline. Vurley is different. It is in a large closed depression, formerly a glacial lake, high up on the plateau. Some 15,000 years ago 7 metres of fine loess blew into the depression and sealed the cave. Possibly before that there was a lot of infill into an open cave which has now partially washed out. You can see the choke has been washed clean. Vurley lies on faults associated with The South West Overthrust and is in Clifton Down Limestone.

Send these Photos to BGS  British Geological Survey at Nottingham .
I am sure they will respond .
I would have said before breaking  it looked like Jasper but not after !

Nearest I can find in the Boys Book Of Rocks & Minerals is Pink Microgranite.

Looks like an iron ore.  Is it magnetic?  Does it fizz when you pour conc HCl on it?

Don't know. Looks more like quartz grains than crystals to me in a hematite cement, and I think there's a suggestion of layering in the middle image. Not sure how hard such sandstone would be though.

Robin

It is probably haematite, possibly replacing oolitic limestone (?) and may be associated with mineralisation on the southwestern overthrust. Do a streak test by scraping the rock across a piece of unglazed porcelain - it should leave a reddish or reddish-brown streak.

Is it very dense (haematite is)?

Ahh. Thanks all. Its is heavy and dense and looks just like this haematite museum specimen.

Now that you have identified this pretty rock ,could you please put it back ,
because it looks to me as if it was holding everything up !

Umm. Will give it all a poke tomorrow. :doubt:

Careful, now, O.R.!  You've got scars enough already!

" My kingdom for a long crow bar" 

so tempting!!

I wonder if OR scraped across one his precious pottery bottles

Maximum effort today with seven people hauling. Only blood spilled was from Pete Rose for a change.