Through a generous grant from the National Society of the Colonial Dames, Oakland’s preservation team was able to undertake the meticulous task of cleaning the many female statuary of Oakland. Most of the 27 angels and depictions of loved ones are carved from fine materials such as Vermont and Carrera marble.
As you may notice on your visits to the cemetery, monuments and statuary often bear a veil of black grime. The cleaning process requires a delicate touch and a specialized chemical agent to remove the invasive elements that degrade the stone over time. This black “biofilm” is actually colonies of micro-organisms comprised of various algae, fungi, and bacteria. The biofilm takes root within the stone and secretes acid which slowly degrades the marble. Its characteristic black color acts as a protective barrier shielding microcolony from the sun’s radiation.
The fine details and crevices of the carvings create the ideal environment for gypsum to form. This crystalline crust is created when the porous stone’s calcium carbonate minerals are exposed to water and salt from rainwater, causing the material to undergo a chemical change. The color of the gypsum is dependent upon the pollutants in the atmosphere. Since Atlanta is a city of transportation, carbon is our primary pollutant resulting in its black color.
Removing the grime from Oakland’s female statuary requires a gentle hand and an abundance of patience. Our preservation specialists use a soft-bristled brush much like a toothbrush and a biocide solution. The solution is D/2, a biological cleaner that is highly effective at removing mold, mildew, algae, lichens, and air pollutants but harmless to plant life. Tested and used by the National Park Service, D/2 is biodegradable, pH neutral, and contains no salts, bleach, or acids.
See before and after photos of the statuary below.