Thats what I use for bases. I buy mine at Home depot.I glue the mosiac material either broken pottery or glass tiles on the bought paver. I use Clear Liquid nails for the adhesive. This I get at Wal mart very inexpensive
. I find this holds up the best out side all winter. Then I use sanded grout and a sealer and I find it has worked great for me.

Hi Fleur
I find glass to be tricky unless I acid etch it first. I just etch the side that touches the mortar and it sticks very well.
I picked up a quart of the acid from a stained glass place and it lasts forever.

Backyard Living Magazine just published an article on how to do this. Great magazine.

Here is a link that might be useful: Cake frosting stepping stones

Thanks seedbandito. I just copied it off.

Sidewalks are being broken up and replaced everywhere in this country.
Finding a pile of old broken concrete doesn't usually take that much searching.
These broken irregular chunks of side walk make a great base for this technique.
They are free as well.
I did a whole bunch of them this spring and everyone loved them.