Slate- Can it be collect from local creeks?

[swimfin27]

I am looking into making some slate caves and structures. The slate available at the LFS is minimal and expensive IMO(2.19/lb). I am an avid angler and my local area offers some of the best creek fishing around. These creeks are lined with what I have always thought and referred to as Slate. It flakes away pretty easily resulting in longer pieces and can be carefully split into many thinner pieces. We used to collect it for our parents to be used in the garden or turtle tanks.
I would like to setup an expirement with 2-10g tanks but I currently only have one so with no control tank to compare to would be useless. 

Has anyone else used slate from local areas?

Can there be effects on your water parameters? I imagine a specific answer to this would have to be determined by the type of rock it is?
 

[Carl]

I have used many rocks from local areas, but not slate

What you can do is soak it in a saltwater/brine solution for 24-48 hours.
Then rinse and add it to another bucket with pretested water for pH, GH, & KH. Leave over night and test again.
If no dramatic changes I would assume safe

Carl

[angelminx]

I don't know what slate consists of, but one way to test rocks for (H2O chemistry) safety is to put a drop of (if I remember corectly) muriatic acid, and if it bubbles, the rock will affect you KH (raise it).

[parker002]

Angelminx is correct, you can test for reactivity in limestone and other alkaline mineral deposits using an acid like Muriatic, which can often be found at pool and spa stores.

The one other thing you need to be careful of is the actual hardness of the stone. Slate is a foliated sedimentary rock and can often fall apart when exposed to underwater conditions for long periods of time. Make sure it's REALLY hard before you use it. I've had slate and sandstone in my pond that disintegrated after a couple of seasons of exposure, while other pieces survive to this day.

[angelminx]

Great info, Parker !  I never knew that about slate possibly falling apart after being underwater for a while ,  but how would you test it for strength?

[parker002]

Hit it with a hammer.

[swimfin27]

Great information!

What kind of tips does everyone have for cleaning their stones, slate and other natural finds?

[parker002]

For non-porous materials, I usually use bleach.