Editing NIST stone test wall (section)

[[Image:Nist stone test wall.jpg|thumb|300px|right|The NIST stone test wall.]]

The '''NIST stone test wall''' is an experiment by the United States [[National Institute of Standards and Technology]] to determine how different types of [[construction]] [[rock (geology)|stone]] weather. It includes 2352 samples of stone from 47 US states and 16 countries. The wall measures approximately 12 m long, 4 m high, 0.6 m thick at the bottom, and 0.3 m at the top.

It includes varieties of [[andesite]], [[argillite]], [[basalt]], [[bluestone]], [[breccia]], [[conglomerate (geology)|conglomerate]], [[coquina]], [[coral]], [[dacite]], [[diabase]], [[diorite]], [[Dolomite (rock)|dolomite]], [[gabbro]], [[gneiss]], [[granite]], [[granodiorite]], [[Greenschist|greenstone]], [[labradorite]], [[limestone]], [[marble]], [[basalt|melaphyre]], [[pitchstone]], [[pumice]], [[pyrophyllite]], [[quartz]], [[quartzite]], [[sandstone]], [[schist]], [[serpentinite]], [[Coquina|shellstone]], [[soapstone]], [[syenite]], [[travertine]], and [[tuff]].

The wall was built by one [[stonemason]], Vincent Di Benedeto, in 1948.  He used two types of stone-setting mortar on the front. He used both a 1:3 [[lime mortar]], with a high [[calcium hydrate]] and a 1:0.4:3 [[portland cement]], [[calcium carbonate|whiting]], and [[Mortar (masonry)|sand mortar]].

The wall was moved from its original location in [[Washington, D.C.]] to [[Gaithersburg, Maryland]] in May 1977.