Rough stone from the quarry is usually sold under two classifications, rubble and dimension stone. Rubble includes the pieces of irregular size most easily obtained from the quarry, and suitable for cutting into ashlar 12 inches or less in height and about 2 feet long. Stone ordered of a certain size, or to square over 24 inches each way, and of a particular thickness, is called dimension stone. The price of the latter varies from two to four times the price of rubble.
Rubble is generally sold by the perch or car load. Footings and flagging are usually sold by the square foot; dimension stone by the cubic foot. In Boston granite blocks for foundations are usually sold by the ton, and rubble for foundations is often sold that way in various localities.
In estimating on the cost of stonework put into the building, the custom varies with different localities, and even among contractors in the same city.
Dimension stone footings (that is square stone 2 feet or more in width) are usually measured by the square foot. If built of large rubble or irregular stones the footings are measured in with the wall, allowance being made for the projections of the footings.
Rubble work is most often measured by the perch, which consists of 24¾ cubic feet in the East and of 16 2/3 cubic feet (by custom) in Colorado, and in some localities 22 cubic feet are called a perch.
If work is let by the perch it should be distinctly stated in the contract the number of cubic feet that are to constitute a perch, as the custom of the place would probably prevail in a dispute. It should also be stated whether or not openings are to be deducted; as a rule rubble walls are figured solid, unless the opening exceeds 70 square feet.
Occasionally rubble is measured by the cubic yard, or 27 cubic feet, and by the cord of 128 cubic feet.
Stone backing is generally figured the same as rubble.
Ashlar is almost invariably measured by the square foot, the price varying with the kind of work and size of stones. Openings are generally deducted, but width of jambs measured in with the face work. This custom varies, however, with different localities and kind of work. In common rock-face ashlar the wall is often figured solid unless the openings are of unusual size.
Flagging and slabs of all kinds are always figured by the square foot.
Mouldings, belt courses and cornices are usually figured by the lineal foot, irregular shaped pieces by the cubic foot. All carving is figured by the piece. Some contractors figure all kinds of trimmings by the cubic foot, varying the price according to the amount of labor involved. Others figure the cubic feet in all the stone to get the value of the rough stone, and then figure the labor separately - so much per lineal foot for mouldings, so much for columns, and a separate figure for carving. This is the most accurate method, and is usually employed by contractors for granite work. Of course considerable experience is necessary to know how much to allow for labor; the value of the stone itself can be very easily computed.