Granites are formed of an aggregate of crystals which are molded together without any interspace between them or which enclose one another. The magnificent crystallinity of granite is a striking characteristic." Geology of Granite, E. Raguin, London, 1965 p.3
It is accurate to speak of "granites," because many varieties of the stone exist. While they differ in color, texture and crystalline structure, the granites have three essential minerals in common:
* Feldspar (50% or greater)
* Quartz (25-40%)
* Mica (3-10%)
These minerals occur in different proportions, giving each granite its own color, texture and structural characteristics. In addition, hornblende, magnetite, hematite, pyrite, zircon, garnet, corundum and other minerals may be present in smaller amounts, adding to the unique coloration and texture of each granite deposit. In supplying granite for all large building or complex of buildings, it is essential that the stone be consistent in color and texture. To assure this, each granite color must be quarried from the same deposit. With natural material like granite, a certain amount of "movement" or grain in the stone must be expected. Many people find this flow and blending of colors to be the most compelling reason for using granite.