Selecting Bluestone

Bluestone is a versatile and relatively affordable attractive stone, which is primarily sourced from quarries on the East Coast, such as Connecticut and Pennsylvania.

The ‘main’ colors mentioned for Bluestone paving are ‘Full Range’ and ‘Select Blue.’  Full range generally has mix of different stone colors including silver / blue, brown, tan, grey, rust and even green and plum. Select blue is primarily a mix of blue and grey tones. The color variations will be determined by the quarry or saw shop that the stone is pulled from.  As stone is a natural element, these colors can change on a daily basis.  ‘Lilac’ is another color which is a grey with a green tinge. Below is an image of a completed ‘Select Blue’ bluestone patio on one of our projects.

Select Blue Thermal Finish Bluestone Paving

Source: Terra Ferma Landscapes – Grand Experience

For finishes, when stones are cleaved or separated along a natural seam, the remaining surface is referred to as a ‘natural cleft’ surface. The alternative is ‘thermal’ or ‘exfoliated’. This process incorporates water and heat to reveal the natural layers of the stone as it was deposited originally. The cutting orientation must be almost exactly along the horizontal layers. The cut slab surface is soaked with water and heated rapidly with a wide nozzle propane torch, breaking off chips of stone along their natural fault lines. If the initial deposit was made under slow moving water the ripples of the water action on the sand or mud will be revealed. This deposition process may be seen today at any ocean beach in shallow water or in a stream bed where conditions allow it to be observed. Thermal finishes are commonly applied to bluestone to make the material more hard-wearing and have a smoother feel to the touch.

‘Washed’ finish is also available. Washed bluestone has rounded edges.

Full range natural cleft finish bluestone

Full Range Natural Cleft Finish Bluestone

For the thickness of the stone, Pieces are cut to exact dimensions so coverage is dependent on how much you buy. A typical pallet of 1.5″ bluestone will cover an average of 180 square feet; a pallet of 1″ will cover 220 sq. ft. Generally speaking 1″ is used mortared to a concrete, while 1.5″ is required when using a gravel base (a base made of Base Rock, Stone Dust, Sand, etc.).

When selecting bluestone, as it is a natural material, there is the potential for imperfections in the stone. As the stone is often freshly hewn from the quarry, as the stone is exposed to air and the elements for the first time and acclimates, previously unseen imperfections become apparent as the stone chemistry changes. This may happen after the stone has been installed. Some imperfections include; efflorescence and rust marks. This can be minimized by selecting stone that has been out of the ground for a good period of time or by sealing the bottom side of the stone to minimize the movement of water through the stone. Also, if ‘full range’ color is selected, as the there is a wide range in colors and tones, the imperfections are better hidden. Below is a close up image of Thermal Finish, ‘Select Blue’ Bluestone.

Select Blue thermal finish bluestone close up

Source: Wickistone