• Pennsylvania bluestone is often used for patios.patio with a view image by Tracy Horning from Fotolia.com
  
  Pennsylvania bluestone is dense sandstone found only in Northeastern Pennsylvania and South Central New York. Typical uses for this sedimentary rock include landscaping, especially for patios, walkways, walls and stair treads. Inside the home, its uses include countertops, floor tiles and windowsills. It is typically a blue-gray color, but also comes in other natural tones.
  
  

Color

• Contrary to its name, Pennsylvania bluestone comes in a variety of colors. The most typical is blue-gray, called ''true blue'' bluestone. Other colors include gray, green, lilac, red and a combination of all these colors.
  
  

Durability

• Pennsylvania bluestone is a prized building material because of its durability. It is strong, won't discolor and resists cracking. It easily separates into similarly sized slabs for landscaping purposes. Bluestone has a natural, nonskid quality, making it desirable for walking surfaces such as pathways, patios and stair treads.
  
  

Widths

• There are two types of Pennsylvania bluestone. The ''natural cleft'' variety is quarried, cut and separated into layers of several thicknesses for flagstones. The second type is quarried in thick chunks, which can weigh as much as 30 tons.