Trim Lapidary Glass Slab Saw,Lapidary Slab Saws is perfect for cutting facet material, opals and rock slabs of all types. With a 8" blade capacity, the depth of cut is 1-3/16" and the maximum vise opening is 2-3/4". A general rule of thumb for choosing a saw: Anticipate what the maximum size would be of the largest rock you would be cutting and choose a (blade) size at least 3 times as large as the material you wish to cut.