Hi Jeff, I never thought of the landscaping places. Good lead, thanks!
I went to our local fish store this AM to get crickets for our
little toad and snooped at aquariums etc. I noted they had all manner
of different rocks, starting at $2.99/lb for the same lava rocks I
picked up for free along the roadG.

I'm wondering if the pieces I got are slate instead of shale. Have to
look closer at my books. Whatever it is it's flat, dark gray in color
and splits fairly easily lengthwise. You can see the grain lines
running lengthwise. As time passes I'll learn a lot more about rocks
and fish both and do a much better job of describing and IDing them.

Grandpa John

Jeffrey St. Clair, Ph.D. wrote:
Hi John,

Nice to meet a fellow rock fan as well! You could also find a nice flat
slab of marble or slate, shale's harder cousin. Do you have any landscape
supply shops near by? They usually sell in bulk to home builders and pool
builders, but it's been my experience they'll let you have a dozen rocks for
around 10 bucks.