Hardness and Beauty,
All in One

By Kate Parrott

Granite is one of the most commonly occurring and widely used stones in the world; in fact, it is thought to be the most abundant type of stone making up the continental crust. Granite is an intrusive, igneous rock that is formed by the slow cooling and crystallization of magma beneath the Earth's crust. The rock has a visibly crystalline texture, creating a unique, beautiful look, which is also incredibly durable. Granite offers permanence in color and texture, making it a suitable stone for a variety of building projects. In architecture, granite is generally classified into two categories: building granite and masonry granite. Building granite is used either structurally or as a veneer for exterior or interior wall facings, steps, paving, copings or other building features, while masonry granite is used in larger blocks for retaining bridges, bridge piers, abutments and arch stones.

More Info Quarry Locations: North America: Canada, Mexico, United States South America: Argentina, Brazil, Columbia Europe: Austria, Belgium, the Czech Republic, Finland, France, Germany, Italy, Norway, Portugal, Sardinia, Spain, Sweden, Switzerland, Venezuela Africa: Angola, Egypt, Madagascar, Namibia, Nigeria, South Africa Asia: China, Egypt, India, Iran, Saudi Arabia, Sri Lanka, Taiwan, Thailand, Turkey, Ukraine, Vietnam Australia Applications: Architectural accessories Interior accessories Building stone Countertops Fireplaces Flooring Landscaping Appropriate Finishes: Bush hammered Flamed Honed Polished Sandblasted Sawn (rough) Stone Stats: Average MOHs Hardness: 7 Average Absorption Rate (%): .13 Average Bulk Density (pcf): 172.8 Average Compressive Strength (psi): 23,300 Average Modulus of Rupture (psi): 1,855

Granite generally contains three mineral groups: Quartz ranges from 25 to 35 percent; feldspar from 50 to 65 percent; and dark minerals such as mica, hornblende and magnetite, from one to 10 percent. Other minerals, such as pyrite, garnet and hematite can occur in small percentages, accounting for the wide range of granite varieties that are available. The term "granite" also is often used to describe other plutonic, igneous stones, such as syenite, monzonite, granodiorite and others that all have similar chemical and mineralogical characteristics.

Quarries
Granite is quarried across the globe; in the United States, granite is quarried in various locations throughout the country, including the New England and Great Lakes regions, North Carolina and Georgia, Texas, California and the Midwestern states of Minnesota, South Dakota and Wisconsin. New Hampshire actually has been nicknamed the "Granite State" because of the amount of granite it produces.

Years ago, excavating granite was a timely, laborious process that included the use of a significant amount of explosives and a lot of manual labor in the drilling process. Today, diamond wire saws and slot drilling are the primary activities used to complete the job, making granite more economical for consumers, as well as a cleaner, safer and significantly less labor-intensive excavation process.

Granite quarries are laid out based on the direction in which the granite will break the easiest, providing the maximum benefit that can be attained from the natural seams and structure. By using these natural seams, the maximum yield can be obtained from the quarry deposit, thus reducing the amount of stone produced that is not suitable for use as dimensional granite.

The types of natural fractures that can be seen in a granite deposit are based on their relationship to the flow lines, as well as the surface of the granite deposit. Sheeting joints run roughly parallel to the topographic surface at various levels beneath the surface; longitudinal joints are steep cracks that run parallel to the flow lines; while cross joints are perpendicular to the flow lines.

Colors
Granite is available in a wide variety of colors, including white, black, pink and red. The varying percentages of quartz, feldspar and mica account for the rock's color, veining and crystallization, making each granite deposit unique. The high presence of quartz can account for many of granite's color variations, as quartz can be milky white, rose, smoky, yellow or amethyst. Feldspar, another one of granite's main minerals, can account for a glassy white, blue, green or red appearance. Finally, mica can contribute to a black, green, red, yellow or brown appearance.

Applications
Granite is widely used as a construction stone because of its hardness and durability. The stone offers permanence, enduring color and texture, with the ability to withstand weathering compared to many other materials that are vulnerable to the acidity of rainwater. For this reason, granite is commonly used for monuments, stair treads, countertops, windowsills, street curbing, wall cladding, roofing, flooring and paving.

Second only to diamonds in hardness, granite has a reputation for being virtually indestructible. It is a common paver of steps, terraces, plazas and public spaces. The stone is a perfect solution for anyone seeking a high quality, aesthetically appealing, enduring look. Available in blocks, slabs and tiles, granite's finishes range from polished and honed to sawn (rough), sandblasted, bush hammered and flamed.

Also, granite is an ideal material for monuments. Because it is massive in nature and has a homogenous grain, it is highly effective for decorative use. The stone can take on a good polish, making it pleasing to the eye and is resistant to all types of inclement weather. Granite is also ideal for flooring and countertops; with a wide variety of colors to choose from, granite floors and countertops can match virtually any décor.

Interesting Facts
Granite has long been a stone of sturdy use. Its earliest records date back to ancient Egyptian civilizations 7,000 to 8,000 years ago when it was used as one of the building materials for the pyramids. Granite was also used to build pharaohs' sarcophaguses. Today, a relic of the ancient Egyptian dynasty exists in Paris, France. It is called the Luxor obelisk and is made of pink granite, weighing in at an impressive 250 tons.

Stone Mountain, located in Atlanta, is one of the largest exposed outcroppings of granite in the world, behind only Mount Augustus in Australia and Pena de Bernal in Mexico. The mountain is 825 feet tall and covers 523 acres. The mountain also contains a bas-relief, the largest in the world, on its north face. The relief contains three figures of the Confederate States of America: Robert E. Lee, Stonewall Jackson and Jefferson Davis. The carving is larger than a football field and is recessed 42 feet into the mountain.

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