Granite

a coarse-grained crystalline rock. Typical granite is composed of three elements,--quartz, feldspar, and mica. The prevailing color is imparted by the feldspar, which varies from red to pink. Some granite is very dark. Other is of a light gray color. The three elements are mixed in varying proportions. Sometimes one element is almost wanting. In case the feldspar is replaced by horneblende, the rock becomes a syenite, so called from the Egyptian town of Syene, where it was first quarried. In genuine granite the flakes of mica assume all positions. In case the flakes of mica are made to assume a parallel position, as by enormous pressure, giving the rock a slightly laminated structure, it becomes a gneiss. Geologists are not quite agreed as to the origin of granite. Some say that it was formed by a sediment in the bottom of the ancient oceans and has been greatly changed by heat and pressure. Most authorities assert, however, that it is an igneous rock formed by the cooling of molten masses.

Granite is considered an ancient rock. Where found in connection with sedimentary rocks, such as limestone, it is always undermost and is for that reason called an underlying rock. It is the principal rock of New England. New Hampshire is called the old Granite State. Geologists assert that granite hills may be recognized at a distance by their rounded form, resembling enormous bubbles.

Granite weathers, that is to say, disintegrates, very slowly. Granite hills are not, therefore, likely to be heavily clothed with vegetation. Although difficult to quarry and hard to dress, it is one of the most valuable building stones known. It neither crumbles, weathers, nor crushes. Granite buildings erected centuries ago show almost no perceptible change. A cubic foot of granite weighs from 165 to 170 pounds. Sandstone weighs from 130 to 160 pounds. In estimating the value of quarry products, our granite industry ranks second--next to limestone.