A State of Decay
A large percentage of the stones found in Cemeteries, burying grounds and graveyards are in an advanced state of decay. Many factors have combined to contribute to this degraded condition. Acid rain and localized pollution have combined, along with the elements of nature, to greatly increase the speed at which many landmarks are being defaced or lost altogether. Land development has infringed on graveyards and diminished their historic perspective. Changing attitudes towards death and burial customs have further eroded the interest and respect, which had formally been paid to our fallen ancestors grave sites.
Environmental elements have always been, and will always be, a major source of degradation to our built world. Rain fall rates, freeze thaw cycles, and specific geographic location, all join to determine the rate at which stone will break down, and turn back into the elements from which it was formed. But today, acid rain has become the fastest growing destructive force to much of our heritage carved in stone.
Fossil fuel consumption causes toxic emissions, which then combine with moisture to form acid rain. Acid rain is rainfall which has a lower then normal ph. The ph scale ranges from 0- 14, with 0 being the most acidic, and 14 being the most alkaline. Normal rainfall is slightly acidic. Around the entire world today, most rainfall ranges from slightly acid to very acidic. Regions with higher rates of localized pollution tend to have the worst acid rain.
Acid Rain is a world wide problem not unique to America. Countries around the entire globe including Italy, Egypt and Greece are all striving to protect their built environment in stone and masonry. Priceless sculptures have already been moved indoors to avoid total destruction.
Marble and Limestone are the most effected by Acid rain, as chemically they simply break down, and cant stand up to the relentless acid bath they receive, and are latterly being washed away by the low ph rainwater. Surface details are the first thing to go, with detailed carvings being reduced to faint images. Eventually though, catastrophic failure will follow with the entire carving being lost or the stone snapping under its own weight.
With increasing demands for land and skyrocketing real estate values graveyards are at risk. Luckily many states in America now have laws which intend to protect graveyards.
Yet, overzealous developers are still bulldozing landmarks before anyone has a chance to realize or stop them.
Historically this is not a new trend. Two of the oldest and most famous graveyards in Boston were nearly lost to developers well over a century ago. Both the Granary and the Old Kings Chapel Graveyard had been planned, to be moved across the Charles River to the new Mount Auburn Cemetery. The thinking of the day was simple, why waste such valuable land on some old gravestones? After all would anyone really care if they were moved out of downtown Boston? Yes, the people of Boston did care, they stepped up and protested.
The Hancock mansion had just recently been knocked down, before anyone really knew this was planned. Many other historic landmarks in Boston were next in line for the wrecking ball. The developers figured, who cares about this old stuff? We can just get rid of it, and build bigger, better new structures. The people of Boston cared, they stood up,
they spoke out; they stopped the destruction of many great landmarks. The historic preservation movement in America was founded.
All things constructed from stone, will eventually erode. The forces of nature such as the sun, rain, snow, ice, and wind all combine to wear away and break down stone and masonry, into the elements from which it was once formed. As mentioned above, acid rain is now a leading cause of erosion to most calcium carbonate based stonework, which includes marble, and limestone.
The rate at which rock erodes various greatly based on what kind of rock it is. Built on a solid granite foundation, the Great Pyramid of Giza is the only structure remaining, from the seven ancient wonders of the world. The ancient Egyptians knew granite was the most enduring natural stone, yet it was not until the recent past that we have come to take advantage of granite in cemetery monuments.
In the Stone ID section, varying decay rates are touched upon. Generally speaking the harder the stone, the longer it will last.