Granite & Natural Stone
Natural stone countertops provide an aesthetic beauty and durability that can only be found in nature. Granite is the most popular stone surface in terms of overall sales, with marble, soapstone and limestone used to a lesser extent.
From The Earth
Natural stone is one of the oldest building materials known to man. It is classified in three distinct categories: Igneous (granite), metamorphic (marble and soapstone) and sedimentary (sandstone and limestone). Sedimentary rock, which is formed by settling and compaction of materials, is the softest of the three and is generally not appropriate for use in kitchen countertops. Metamorphic rock, which is formed from other rock through heat and pressure, is also fairly soft but, depending on its density, can be used in the kitchen or bath. Igneous rock, which is formed by magma (molten rock) cooling and solidifying, is typically the hardest and best suited stone for countertops. The hardness of granite is well-known and there is no shortage of it, as it is the most abundant stone on Earth.
Granite, marble, and soapstone are quarried from the earth in large solid blocks. These large pieces are then further cut and refined into functional sizes appropriate for specific use as either slabs or smaller blocks. There are many quarries throughout the world and even more companies that provide natural stone slabs for use in countertops.
About The Slabs
Prior to fabrication into countertops, granite is cut into slabs that range in thickness from ¾ inch (2 cm) to 2¼ inches (4 cm) with the standard for kitchen surfaces being 1¼ inch (3 cm). After cutting to size, the slabs are often resin sealed with an epoxy or polyester coating and cured for a short time in ovens, depending on the composition and the particular quarry company. Although this sealing process has been in practice since the 1960s, it has become common in recent years and it is thought that soon all stone cut for consumers will be resined to provide further durability.
Once sealed and the applied resin has cured, the slab is polished to bring out its natural veining and luster. Although special finishes, such as a honed finish, are available, the vast majority of granite slabs meant for use as countertops receive a high polish finish.
One of the great selling point of natural granite countertops is the variety of colors and patterns the materials possesses. Granite is composed of varying quantities and dispersions of quartz, feldspar, mica and other crystalline rock that makes it available in a rainbow of colors. Tan and beige granite has traditionally been the most popular while blacks and grays have come into fashion in recent years. Other colors include varying shades of red, green, blue and purple, although there is virtually a limitless variety of colors and patterns.
Marble & Soapstone
Marble is thought of as highly desirable as a countertop surface for baking preparation, but cannot be recommended for an all-purpose kitchen surface because of its softness, susceptibility to abrasions and staining.
Soapstone, relatively soft compared to the major stone types for countertops, is the densest. Its density makes it virtually impenetrable by liquids and stain resistant, making it suitable for kitchen and bath applications. It is also more heat resistant than other natural stone materials. These properties also make it a leading surface in chemistry labs and outdoor kitchens.
Natural Stone Resources (PDF Documents)