10 Stones to Use in Your Hardscape

One option for garden hardscaping is limestone. It's a sedimentary rock, or a stone that's made up of eroded grains of rock, fossils and plants, along with mud and sand that's compressed and packed together. Limestone comes in a range of colors from white to red and black [source: The Stone Network].

Traditionally, limestone has been used in many building projects, including the Empire State Building in New York City [sources: Public Broadcasting System, Hill]. Limestone, like most natural stones, can stand up to the elements outside. For hardscaping purposes, limestone works well as a wall stone as well as a stone for creating flooring such as patios or walking paths [sources: Lawrence, First].

It's important to note that limestone is rated by ASTM International, an organization that develops standards for items such as materials and services based on how it performs under different situations. These ratings should be taken into account when choosing your stone [sources: ASTM International, Roehrig]. "An ASTM Type I limestone represents the lowest performance classification of limestone and may be unsuitable for applications requiring low water absorption, high wear resistance and strength," says Peter Roehrig, general manager at Valders Stone & Marble, Inc. "Type III limestone, on the other hand, is suitable for virtually any exterior use or application due to its high strength, low absorption [and] high wear resistance."

Sandstone, another sedimentary rock, works well for outdoor applications. While limestone may incorporate a number of once-living plants and animals into its composition, sandstone is created when grains of sand, along with other minerals, are cemented together over time to produce a rock ranging from reddish brown to white [sources: Bradley-Hole, Pough].

Sandstone makes a good paving stone because it can easily be broken into thin slabs [source: Bradley-Hole]. It's also a good choice if you're going to be creating a retaining wall or a privacy wall [source: First]. A sandstone wall can add height to your garden landscape. To take it one step further, train a climbing vine onto the wall for a splash of color and natural appeal.

Smaller sandstone boulders can also be used as accent rocks around streams or within landscape beds [source: Lang Stone Company].

Bluestone is a distinct type of sandstone and best known for its bluish-gray color. "Bluestone is one of the most popular flagstones -- particularly in the northeast," says Liz Pulver, a landscape architect registered in New York and California.

Just like other sandstones, bluestone can be used for many different hardscaping projects. It can be used in applications such as walls and flooring. Its durability makes it a good choice for outdoor steps as well [source: Flynn Stone Rocks]. In boulder form, the color of the rock can draw attention as a focal point for a rock garden. Place a bluestone bench in a special nook of the yard for seating as well as a splash of color [source: Hawk Brothers Mason & Patio Supplies].

Quartzite actually starts as sandstone. Through compression and heat, the sandstone is changed, or metamorphosed, into the new metamorphic rock [sources: Lambert and the Diagram Group, Harding, Symes and Taylor]. Quartzite is very hard and dense, which makes it a good choice for weathering outside in the elements [source: Powell]. It comes in a range of colors, including white, yellow and gray [sources: Powell, Pough]. Quartzite can give off a shiny appearance, which can make it a showstopper at night, since the stone can give off a glow in the moonlight [source: Pacific Stonescape].

Its luminescent quality and durability make quartzite a logical choice for landscaping applications. It's most commonly found in landscapes in the western states of the United States due to ease of access [source: First]. Quartzite is often used as a flooring component since its durability helps it to stand up to many years of wear and tear underneath feet [source: Pacific Stonescape]. Another application for quartzite is as decorative gravel in flower beds or on paths [source: Geo. Schofield Co. Inc.].

Popular for indoor kitchen countertops, granite is now also being used in outdoor kitchens as well. Granite is an igneous rock, meaning that it comes from magma deep within the earth that was slowly cooled to create rock [source: Harding, Symes and Taylor]. Granite has large, course crystals of quartz, feldspars and mica [sources: Bradley-Hole, Harding, Symes and Taylor]. Granite's different minerals can give it a speckled look ranging from an almost black to a cream [source: Harding, Symes and Taylor].

Granite is a good choice for outdoor areas, because it's hard and nonporous [source: Bradley-Hole]. "It will stand up better than virtually any other material you can think of," says Larry First, president of Lang Stone Company.

For granite countertops, you might want to think about two different surface applications as opposed to the high polish usually done in indoor kitchens. A leathered finish gives a more matte look and can blend more into the natural setting, while a brushed finish can give the top a rougher surface [source: First].

Granite's other applications outdoors include flooring as well as accent boulders and occasionally even gravel [sources: First, Geo. Schofield Co. Inc., Walls, Walks & Patios].

While you may think of slate as a roofing material, it also works well in many hardscaping applications [source: Bradley-Hole]. Slate rocks originally started out as shale that over time metamorphosed into a new rock [source: Harding, Symes and Taylor]. Slate usually comes in a gray, green or blue color, and it easily cracks into thin slabs of rock [source: Bradley-Hole].

Several of slate's natural qualities make it a good choice for specific outdoor applications. Due to the fact that slate naturally breaks into thin pieces, it's a good paving stone [source: Bradley-Hole]. It can also be made into stone tiles that create a floor with a more formal look [source: Walks, Walls & Patios]. Slate's natural water-resistance makes it a good option for near-water features or pools [source: Pools & Spas].

Flagstone can be made from different varieties of rock. A flagstone is made of natural rock -- usually sedimentary stones such as limestone or sandstone -- and is usually about one to two inches (2.5 to 5.1 centimeters) thick [sources: First, Walks, Walls & Patios]. "Flagstone, by definition for us, is material that is tough enough to stand up to the outdoors for a long period of time," says First. "It's relatively thin and flat so that it can be walked on and fairly easily installed."

The slab-like quality of flagstone makes it a good fit for many different areas of the yard. "Flagstones are used most often for paths, patios, stair treads and wall coping," says Pulver.

Flagstones can be irregularly shaped or more uniformly shaped into squares or rectangles depending on your preference. The uniformly shaped versions offer the possibility of a pattern to add a formality or decorative touch to the area you're creating.

Along with style, you have to think about functionality when choosing the right stone for your application. When choosing flagstone for a walking surface, be sure to think about how slick the surface might get when wet; choosing something with a little more texture might help with traction [source: Pulver].

Fieldstones were properly named, because many of these stones were typically found in fields or open spaces instead of being mined out of a quarry [sources: Pulver, First]. These types of rounded stones tend to come in a random assortment of colors, though they're usually categorized by size for purchase [source: First]. These stones can provide a more eclectic feel to a garden.

Fieldstones are most commonly used as wall stones. Fieldstones that are sold as wall stones tend to be larger and provide more depth than a flagstone, allowing for more depth and dimension to the wall [source: Pulver]. These stones work well as free-standing walls or wall veneers, or to create a raised bed for a garden [sources: Pulver, First].

Gravel is used more to describe the size of rock rather than the actual type of rock. Gravel can come in a variety of stones and colors. Due to its small size, people use gravel in a number of different ways around the yard. "I love decorative gravel used as a driveway or a path," says First.

Gravel tends to be an inexpensive option for many areas of hardscaping [source: Lawrence]. For driveways, gravel should be angular, or shaped in a way that will allow it to compact when trod on, instead of round, which can make for a more uneven surface [source: First]. Using gravel as a substitute for mulch in garden beds can provide a lower maintenance alternative [source: Bradley-Hole]. Certain gravels, such as river rocks, look great in a water feature [source: First]. Yet, one place you might want to avoid gravel is around a pool or hot tub, since the small stones can easily make their way into the water [source: Pools & Spas].

Much like gravel, veneer stone can be made from different types of stone. It's still a natural stone product, though it's specially cut for use on the face of a structure. A thin veneer stone is simply cut thinner to allow for more stone coverage and a similar look with less stone used [source: Buechel Stone]. "Many stone blends can now be supplied in a thin veneer and adhered to a wall foundation in lieu of a full thick stone material that requires a structural support ledge," says Roehrig.

Fieldstone, limestone and sandstone are all common stones used to create thin veneer [sources: Stoneyard.com, Buechel Stone, Roehrig].

In a yard setting, thin veneer stones have many uses. Outdoor kitchens and fireplaces are two potential applications for thin veneer stones. Certain manufacturers are now making the shells of fireplaces and outdoor cabinets to specifications needed for covering the products with thin veneer stones [sources: First, Irwin Stone].

Whether you choose to use stone to create an outdoor kitchen area or as an accent in your garden, the wide variety within this natural material allows for a great deal of personalization to create the perfect look for the hardscaping in your outdoor space.