I'm fuckin' lazy, and as I was rummaging around the back of the granite dealer i found this 30 x 30 slab of marble that was less shiny than the others. The granite slab appears to be a pice of a counter top that was broken is is about 40 x 80+ nice and polished. I handed the lady a 100 baht note and was done.
The local, hand-made, fired brick we get up here would be ideal if I could get someone to make me a 40 x 40 slab. The marble is less than ideal but much more porous than the granite.