Brownstone: A trade term applied to ferruginous dark brown and reddish brown sandstone quarried and extensively used for building in the eastern United States during the middle and late nineteenth century. Most later use has been for renovation, repair, or additions to structures in which the stone was originally used. In gravestones, most commonly used as bases, although common in some areas, such as the Connecticut River Valley, for tablestones as well.

Delamination: Separation of layers of stone along bedding planes.

Exfoliation: Peeling or scaling of stone surfaces caused by chemical or physical weathering.

Flaking: A term commonly used regarding gravestones to indicate minor delamination of surfaces or otherwise unsound stone which easily peels off in small sheets or layers.

Granite: Geologically, igneous rock with crystals or grains of visible size consisting mainly of quartz and the sodium or potassium feldspar. In building stone and gravestones, crystalline silicate rock with visible grains. The commercial term includes gneiss and igneous rocks that are not granite in the strictest sense.

Laminated Stone: Stone consisting of thin sheets; stone built up in layers such as slate.

Limestone: Rock of sedimentary origin composed principally of calcite or dolomite or both. Commonly used in gravestones and tomb structures, in some cases considered to be marble.

Marble: Geologically, a metamorphic rock made up largely of calcite or dolomite. As used commercially, the term includes many dense limestones and some rock dolomite. Numerous minerals may be present in minor to significant amounts in marble, and their presences and distribution account for much of the distinctive appearance that many marbles possess. The predominant stone for gravestones in the nineteenth century.

Metamorphic Rock: Rock altered in appearance, density, and crystalline structure and in some cases mineral composition, by high temperature or high pressure or both. Slate is derived from shale, quartzite from quartz sandstone and true marble from limestone.

Sandstone: Sedimentary rock composed of sand-sized grains naturally cemented by mineral material. In most sandstone used for building and gravestones, quartz grains predominate.

Schist: Metamorphic rock with continuous foliation. Splits along foliation and is occasionally found in gravestone use.

Sedimentary Rock: Rock formed from materials deposited as sediments, in the sea, in fresh water, or on the land. The materials are transported to their site of deposition by such forces as running water, wind or moving ice. They may deposit as fragments or by precipitation from solution. Limestone and sandstone are the sedimentary rocks most used for building and gravestones.

Shale: A rock of clay origin, easily split into layers. Occasionally found in gravestones.

Slate: A hard, brittle metamorphic rock consisting mainly of clay minerals and characterized by good cleavage that is unrelated to the bedding in the earlier shale or clay from which it formed. A popular gravestone material of the eighteenth century, particularly in coastal areas. Many of the best-preserved examples of gravestone art are found in slate, and extremely stable stone.

Soapstone: Massive soft rock that contains a high proportion of talc. Occasionally used in gravestones.

Spall: In stone, to flake or split away through frost action or pressure. As a noun, a chip or flake of stone.