Whatever type of stone you want to use Mike. I got mine from a grave yard supplier. The supplier at the grave yard broke a 3-4 inch thick piece by 18x36, I got 2 pieces free around 18x18 in size, but they are at least 100 lb. each. So I had to built a sturdy table with 4x4 legs and 2x4 cross braces and a plywood top surface, to this day I still use the table, but the granite is outside getting ready for an outside table, so I could tool outside when the weather is nice. I just have a 12x12, I gotten from the Hidecrafter supplier when they where just 20 dollars. It is nice, I can move it around when I tool, remove it when I dye the leather. But use the 12x18 inch rubber mat they sell for punching hole under the marble, it dampens the noice. So when I'm really ready to do my swivel knive work, I just remove the 12x12 in. marble from the table and carve on the rubber mat, this prevents the swivel knife blade from getting in contact with the marble. A nick on the tip of the swivel knife blade sure would make a difference. So you need to bring out the Swivel Knife Sharpening Jig and work out the nick on the blade.
I think these are the materials you need to really start.
1. Swivel Knife Sharpening Jig
2. Micro Fine Rouge from the Woodcrafters web site and business cards to rub the green rouge on for stropping your blade.
3. A sharpening stone and sharpening oil.
And practice your swivel knive cuts.