Lee Valley has a lovely set of inexpensive miniature chisels which are an excellent addition to any pewtering toolbox. If your budget allows for it, you might also want to consider the micro carving tool set.
The stone they sell is typically a flat medium gray. Itís soft and fairly easy to work and to see designs on (both at the drawing and carving stages). I've ordered hundreds of pounds of this stone over the years (itís what I typically provide my students), but, as with many soapstones, occasional blocks have had annoying cracks, or small iron inclusions, or narrow crystalline bands.
I buy large blocks (6" x 6" x 12" - 50 pounds) from them which I then cut up. While this is a lot more than most people have any need for, they also now sell much smaller blocks (3 x 3 x 5 ) which can easily be cut into slabs with a hacksaw.
They are located in Ontario, but you can order on their web site. Discounts apply on 5 or more of either block.
They have always been fast and painless to deal with.