Flagstone is a flat sedimentary stone with fissile bedding planes. It is naturally split or cut into layers according to these planes and used for a variety of purposes like patios, fences, roofing, facades, memorials, and walkways. Flagstone is bound together by minerals like calcite, silica, and iron oxide. These internal materials are the cause of flagstone’s beautiful colors, one of which is a stunning blue.
The word flagstone stems from the Middle English word “flagge” which means turf. In the thirteenth century, Europeans began using flagstone for floors, walls, and ceilings. It was especially popular for the interior rooms of castles. Flagstone floors still exist in Scotland’s Muchalls Castle and England’s Lindisfarne Castle. Today, Chicago’s Portage Park is famous for its expansive flagstone decorations.
Pennsylvania has a special flagstone called bluestone that is unique to its part of the United States. Bluestone stems only from the state’s northeastern section as well as New York’s southern tier and northern sections of New Jersey. Bluestone is layered sandstone that ranges in color from a gorgeous blue to green, lilac, rust and more. It developed about 360,000,000 years ago when the seas pushed sand into the Catskills. In terms of composition, Pennsylvania bluestone is made of mica, sand, feldspar, and various minerals. The distribution and composition of these minerals will determine how blue the stone is.
Preparing Bluestone for Use
In order to transform bluestone from the natural state found in the wilderness to stone that is ready to use in homes or businesses, it is cut out of the quarry into cubes. Depending on the density of the stone, the cubes are then treated in one of two ways. The densest stone goes through what is called a spalling process. Once removed from its natural environment, Pennsylvania bluestone is cut along horizontal sections, thoroughly soaked with water and then heated with a propane torch. The spalling process produces thermal flagstone which features a perfectly even finish for the flagstone. However, most cubes will become natural clef flagstone. This results from air-drying for several weeks. During this time, the bluestone will naturally separate along fissures. This separation results in an uneven but beautiful surface. Both termal and natural clef flagstone materials are excellent for any application.
Why Bluestone Is So Appealing
People love bluestone for its distinct color, incredible strength, superior density, and fine grain. It is most often used on decks and patios since it holds its color and is very difficult to crack. Bluestone is also used for walls, steps, indoor floors, and even fireplaces as it can be cut into slabs of specific sizes. Stones don’t come any more durable and strong than bluestone, save for the likes of amethyst. While it is extremely hard, it also has elements of softness, caused by the layering of its component minerals, so that you can enjoy sitting or lying on it as well. This also creates another part of bluestone’s appeal. When covered with water, its rough surface allows pedestrians to maintain a firm grip, making a popular stone for use near pools and water features.
Bluestone Colors, Textures and Patterns
Bluestone may be a gorgeous silvery blue but it is also available in colors like lilac, green, tan and brown. There’s even a special “full range” style color that provides buyers with the entire spectrum of Bluestone colors all in one. Buyers also have the choice of different bluestone textures and patterns including sawn thermal, tumbled, and the always popular natural cleft. Natural cleft patterns are typically sold in 1″ or 1 1/2” thickness. Thermal is usually cut into 1”, 1 1/2” or 2” thickness.
Another part of bluestone’s appeal is that is easy to take care of. It doesn’t require sealing and is cleaned with only water and a brush. If your bluestone is stained, just add some vinegar and water to the surface and scrub it out. The only other maintenance recommendation is a power washing once every few years. Bluestone owners should take care not to power wash on the highest level as it can leave water marks. Some bluestone surfaces develop efflorescence, a white powder that can be easily removed with mortar additives. Otherwise, there are no other cleaning concerns, making Pennsylvania bluestone one of the easiest surfaces for homeowners to maintain.