I have some stone that I am trying to identify. It was installed as an exterior veneer on a house in Alberta.

At the moment, there is about 90 square feet of the stuff in the basement (removed to enable some repairs). I would like to know what type of stone it is.

Below is a photo of a few representative pieces. After some reading online, my best guess is that it is either shale or slate. It is fissile and laminated and the larger pieces are about 1" thick and the smaller are closer to 3/4".

It was installed over steel mesh and mortar and would have been done in the late 80s.

I was initially leaning toward slate, because I didn't think that shale was commonly used for building exteriors. That said, the colouring does not seem right to me for it to be slate.

How would I go about identifying what type of stone this is?

pieces of stone veneer

  • Hello, and welcome to Home Improvement. What's your goal; to find a new supply of matching material? Jun 23, 2018 at 23:40
  • Thanks! Actually, I am trying to decide what to do with the stones that were removed. I am hoping that, once I know what it is, I can do some more research into whether or not it is worth trying to sell (or if I should just use it to keep the weeds down around the far side of the house!)
    – Dave G
    Jun 23, 2018 at 23:51
  • You might have more success by asking at the Earth Science stack. Jun 24, 2018 at 0:39
  • that looks like shale .... fossilized layers of mud .... do you see any fossilized plant material?
    – jsotola
    Jun 24, 2018 at 3:30
  • I examined some of the pieces that are still in place and didn't see any anything that looked obviously like fossilized plant material to me. Not that I'd hang my hat on my ability to detect a fossil of anything that couldn't have eaten me whole at one point...
    – Dave G
    Jul 2, 2018 at 23:22

1 Answer 1


Slate and shale are essentially the same thing, but slate is the "metamorphic" form, meaning it was shale, but changed into a DIFFERENT (more dense) form by eons of time and tons of pressure. So slate would not be fissile ("flaky") to the average expression of human force.

That's shale, aka "flagstone". People use it for siding and walkways, but usually in larger pieces. It might have value to someone, but people generally want it to match the color of something else (more shale / flagstone, house or landscape structure paint, etc.) so I wouldn't waste money buying an ad to try to sell it.

  • Interesting - I didn't realise that's what flagstone refers to. Thanks for the tip about colour matching and the challenges in finding someone interested in it - that's really helpful for context.
    – Dave G
    Jul 2, 2018 at 23:16

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