On Thu, 21 Jan 2010 00:25:15 -0500, "MiamiCuse"
wrote:

I have never drilled through rocks before and I am wondering how different
it will be compared to drilling through solid concrete. I suspect it may be
harder?

I have an exterior wall that is a 12" thick concrete block wall (8" block
with a layer of 4" block), and on the outside of this is a layer of
rock/stone face like this:

http://i173.photobucket.com/albums/w...ckfacewall.jpg

I'm not a geologist but it looks like they might be shattered quartz-
in which case you can only drill them with a diamond bit.

You might try a post to a geology group with a good color close-up of
3-4 rocks. They might be able to ID and tell you where they fall on
Moh's scale. [or you can determine where it falls by scratching
with some known substances-
http://en.wikipedia.org/wiki/Mohs_sc...neral_hardness ]

Most rocks [in my part of the world] are drillable with a regular
masonry bit- no hammering needed.

I'd try drilling first- if that doesn't work, go for the
remove/shatter/re-install that someone mentioned.
-snip-
...I
don't want to end up pushing a piece of rock completely out,

No problem- See above-

and if I can drill into it I don't know how clean the hole will be, will I end up
cracking it into two?

No problem- see above.

I don't have a spare piece of rock or I would try to drill it just to see.


The 'spare piece' is sitting where the pipe comes out. Even if it
ends up getting removed and a new mortar spot has to appear where it
was.

Jim