Custom Granite Countertops
The American Geological Institute (AGI) defines granites as an intrusive igneous rock (cooled slowly in the deep upper part of the Eart’s crust) composed of 25% to 35% quartz and over 50% potassium- and sodium-rich feldspars, with a common accessory mineral of less than 20%, usually muscovite (clear mica), biotite (dark, iron-bearing mica), or hornblende (amphibole).
The color of granite is governed largely by that of the feldpar, usually the most abundant mineral. However, it may be modified to some extend but the quartz, hornblend, or mica, if considerable amounts are present.
Granite is a product of nature with hundreds of varieties available, each possessing unique characteristics. Little can be done to alter the condition in which nature present the varieties to us. Therefore size and color variation may become a factor to consider in the selection of a particular granite.