, minor
differences in structure, texture, and composition, or in costs of
quarrying and transportation, may make all the difference between profit
and loss. Even though all these conditions are satisfactorily met,
builders and users are often so conservative that a new product finds
difficulty in breaking into the market. A well-established building or
ornamental stone, or a limestone used for flux, may hold the market for
years in the face of competition from equally good and cheaper supplies.
The very size of a quarry undertaking may determine its success or
failure.

GRANITE

The term granite, as used commercially, includes true granite and such
allied rocks as syenite and gneiss. In fact even quartzite is sometimes
called granite in commerce, as in the case of the Baraboo quartzites of
Wisconsin, but this is going too far. For statistical purposes, the
United States Geological Survey has also included small quantities of
diorite and gabbro. The principal uses of granite are, roughly in order
of importance, for monumental stone, building stone, crushed stone,
paving, curbing, riprap and rubble. Thirty states in the United States
produce granite, the leaders being Vermont, Massachusetts, North
Carolina, Maine, Wisconsin, Minnesota, and California.

BASALT AND RELATED TYPES

Basalt and related rocks are sometimes included under the name "trap
rock," which comprises,--besides typical basalt and diabase,--fine-grained
diorite, gabbro, and other basic rocks, which are less common in
occurrence and are similar in chemical and physical properties. The
principal use of these rocks is as crushed stone for road and ballast
purposes and for concrete. They are produced in some fifteen states, the
leaders being New Jersey, Pennsylvania, California, and Connecticut.

LIMESTONE, MARL, CHALK

In the United States limestone is used principally as crushed stone for
road material, railroad ballast, concrete, and cement, as fluxing stone
for metallurgical purposes, and in the manufacture of lime. Minor uses
are as building stones, paving blocks, curbing, flagging, rubble, and
riprap; in alkali works, sugar factories, paper mills, and glass works;
and for agricultural purposes. For the making of cement, in
metallurgical fluxes, and in most of the manufacturing and agricultural
uses, both limestone and lime (limestone with the CO_2 driven out by
heating) are used. Lime is also extensively used in the making of mortar
for bu