• A number of foces will weather headstones over time.headstone image by Ken Marshall from Fotolia.com
  
  Gravestones are commonly used to mark burial plots once the body and the casket have been placed inside the earth. When they're new, headstones mark out the name of the person buried in the grave, along with their birth and death dates, in addition to other details that the family adds. Over time though these headstones will wear away in a process called weathering.
  
  

Wind

• Wind may not seem very strong, but over time it can do a lot of damage to stone. Since headstones are set up so that they stand up surrounded by lots of open space, it provides a perfect corridor for wind to blow through. The wind puts pressure on headstones, and over time that pressure can cause cracks to form and edges to round. In addition wind might carry grit in it, which can act as a low powered sand blaster over time. That grit can pock and then groove headstones, wearing them away.
  
  

Rain

• Rain can also damage headstones over long term exposure. The impact of individual raindrops isn't terribly important, but over time the impacts of the rain can wear away at stones. Since headstones stand all by themselves it means they don't have any protection from the rain. Additionally, if acid rain is present then the acidity of the rain could eat away at the stone and cause more damage than normal, base rain might. This is particularly true for susceptible materials like limestone.
  
  

Temperature

• When headstones are exposed to heat and cold, that heat and cold swells and shrinks the stone respectively. This isn't normally a problem if the temperature moves slowly and allows the stone to adjust, but sudden temperature changes can snap the stone by making the swelling or shrinking happen too fast. Additionally, if there is water present either on or in the headstone and that water freezes into ice, that ice will put pressure on the headstone. If that pressure is too great, it will crack and damage the stone.