Wait — I thought granite was formed under the earth’s surface?
It is — the large size of the crystals in granite rock indicate that granite is an igneous rock, formed by slow cooling of magma underneath the earth’s surface. These large deposits of granite become exposed above the surface, forming cliffs, mountains, and other natural structures, by both the movement of the earth’s tectonic plates or the erosion of overlying rocks.
Why is it such a popular countertop material?
It’s popular for a variety of both interior and exterior building projects — it is strong enough to support a significant amount of weight, durable and scratch-resistant, weather-resistant, and can be polished to a high shine. It also goes through a process called case-hardening, which causes granite to become even harder with age.
In exterior projects, such as building exteriors, bridges, pavement, and monuments or statues, granite is used both rough-cut and polished. Polished granite slabs and tiling are more popular than rough-cut for indoor projects, including countertops, backsplashes, flooring, stair treads, and more.
Granite has also long been a popular material for gravestones and memorials, due to its stateliness and durability. It wasn’t until the 18th century, and the invention of steam-powered cutting tools, that granite headstones were able to easily be marked and carved — prior to this invention, they were hand-carved, resulting in poor readability.
As a countertop material especially, granite is popular because it meets a sweet spot of durability — it resists most abrasions, water, mold, and heat and has a low chemical reactivity — quality, and aesthetics that make its relatively higher price fair. It also comes in such a wide variety of colors and crystal content that makes it easy to find a color and grain you love.
What are the different types of granite?
When it is quarried, granite is collected both as crushed rock and large stone slabs — called dimension stone. As crushed rock, it is widely used in both road construction and railroad beds. While crushed limestone is the most popular crushed rock in the U.S. (70% of crushed rock is limestone), granite is the second most used crushed rock, representing 16% of crushed rock consumption, or 265,000 tons per year.
Approximately 400,000 tons of slab granite (27% of all dimension stone) are produced each year in the U.S., second, again, only to limestone in terms of volume and popularity. As we’ve mentioned, granite can be either rough-cut or polished, and used as slab countertops, building stone blocks, tiles, pavers, and crushed stone.
When it comes to different granite colors, they mostly range from pink and white to grey and black.
When granite is mostly composed of quartz (a milky white color) and feldspar (a more opaque white), the result is white granite. White granite, however, is never 100% white due the presence of other minerals, so it will typically take on a “salt-and-pepper” look, with the white “salt” being the most prevalent. This creates a stone that is primarily white with small black “pepper” specks, generally the mineral amphibole.
Some of the more popular named types of white granite include:
- Kashmir White, a metamorphic white rock with deep red crystals, made mostly of white feldspar and quartz
- Giallo Ornamental, primarily white from feldspar and quartz
- Bianco Antico, mostly white quartz with pink feldspar specks
Similarly, black granite is never 100% black — it will generally have specks of other, lighter colored minerals as well. It is also not technically true granite, but more likely another igneous rock called gabbro. What makes it not a true granite? Black granite doesn’t contain 20% or more of quartz. Because of its similarity to granite both in makeup and aesthetics, however, grabbo is commonly, commercially referred to as black granite to simplify material selection.
Some of the more popular named types of black granite include:
- Absolute Black, a type of grabbo
- Black Galaxy, a type of grabbo that is black with golden specks
- Uba Tuba, mined in Brazil, Uba Tuba gets its color from mica
Black and White Granite
Black and white granite is a true granite, composed of more equal parts quartz, amphibole, and feldspar than white granite. This is one of the most common types/colors of granite and one of the most popular materials for countertops.
One of the most popular named types of black and white granite is Black Pearl, a grabbo with both ampibole and pyroxene.
Brown granite is a common choice equally for its neutral tones and rich variety of colors. Brown granite ranges from light and golden tans to deep chocolate and even burgundy browns, and can feature both large and small quartz crystals.
Some of the more popular named types of brown granite include:
- Venetian Gold, tan and white quartz and feldspar with black, grey, and red specks from amphibole, mica, and garnet
- Tan Brown, large amounts of feldspar with small amounts of potassium for a pinkish tint, along with brown and black specks, likely from amphibole
- Baltic Brown, similar to tan brown, with larger grains of feldspar
An abundance of the mineral potassium feldspar, combined with small amounts of quartz, amphibole, and even white feldspar, gives pink granite its salmon color.
Some of the more popular named types of pink granite include:
- Copper Rose, featuring waves of pink feldspar through milky quartz and dark specks
- Milford Pink, a light pinkish gray with dark greenish-gray spots from soda lime feldspar
Red granite gets its color simply from a variation of potassium feldspar which causes its pigment to be more red than pink. These granites are among the most rare and sought-after types of granite.
Some of the more popular named types of red granite include:
- Santa, or St. Cecilia, with many deep reds along with tans from feldspar, quartz, and biotite
- Imperial Red, a deep burgundy
- Havana Red, a reddish brown quarried in Saudi Arabia and China