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Vermont Symbols, Rocks: Granite/Marble/Slate

Granite/Marble/Slate

Adopted in 1992.

Vermont's complex geology has led to the development of a diverse and economically healthy minerals industry which began in Vermont over 200 years ago. Because three of Vermont's rocks are equally important to the state's economy, all three - granite, marble and slate - were formally recognized as State Rocks by Act No. 221 of 1992.

Granite

Granite is an igneous stone, one that is produced by intense heat. Granite is formed from liquid magma deep beneath the earth. Extreme pressures and a slow cooling process bake granite into one of the hardest and densest stones on the planet. Igneous rock found along the entire length of the eastern part of the Vermont. It is mainly composed of feldspar, quartz and mica. The granite from Barre is world-famous, and the Westmore-Morse Quarry in Barre is the world's largest monumental granite quarry. Vermont granite is exported to many states and countries for use as building stone and is prominent in the Vermont State Capitol.

Granite: Barre, Coble hill, and Millstone hill quarries, fine-grained, used in State houses; Black mountain, Dummerston, Windham county; Ascutney mountain, Chester, Cavendish, Pomfret, and Berlin. Extensively quarried at Brunswick, Essex county, known as “Nulhegan granite”; Ryegate, Caledonia county, “Blue mountain granite”; Victory, Essex county; Browngington and Derby, Orleans county; and Woodbury, Washington county.

Marble

Metamorphic rock composed of the mineral calcite, can generally be found in southwestern Vermont. The marble quarry in Danby is the world's largest underground quarry, covering twenty acres. Vermont marble ranges in color from pure white to black. Danby marble was formed about 300 million years ago. It has been used in building Radio City Music Hall, the National Art Gallery, the Jefferson Memorial and the Vermont State Capitol.

Marble:

1. Vermont marble; extensive quarries on western side of Green mountains, in Addison, Bennington, and Rutland counties. Most noted quarries in towns of Middlebury, Sudbury, Brandon, Pittsford (several quarries), Rutland (a dozen or more quarries), (a) Clarendon, Wallingford, Tinmouth, Danby, Dorset, and Arlington—a belt 65 miles long, Vermont Italian marble from Dorset. Most extensive quarries in Rutland, Shelburne, Addition county; at Swanton, Franklin county, dove-colored marbles.
2. Winooski marble, worked to a limited extent in northwest part of State—Addison, Chittenden, and Franklin counties; also, localities at Mallett's bay, Colchester, near Burlington, and to Swanton.
3. Plymouth marble, Plymouth, Windsor county, a variegated marble.
4. Isle la Motte marble, Isle la Motte, Lake Champlain; and in Champlain valley, a black marble.

Slate

Metamorphic rock found in southwestern Vermont. It is formed by the compaction and heating of clay, silt or mud. Vermont slate varies in color from red, green, black and purple. Because it splits into thin slabs, slate is used for roofing shingles, sidewalks and floor tiles.

Slate: Three ranges of roofing slate:

1. Eastern, clay slate near Connecticut river, from Massachusetts line to Essex county; found in Guilford, Windham county; Thetford, Orange county; Waterford, Caledonia county; and other localities and small quarries.
2. Middle range of clay slate extends from Memphremagog lake to Barnard slate quarries in Northfield, Montpelier, and elsewhere of uniform shade and black.
3. Western Vermont slate quarried largely in Castleton; also in Fairhaven, Poultney, Wells, and Pawlet, Rutland county; generally of a dark purple color, with occasional blotches of green; very compact and fissile. Large quarries near West Castleton, Hydeville, Scotch hill, and Fairhaven.

Among the most popular, the hardest, and the oldest of geosymbols, granite is an official symbol of New Hampshire, Massachusetts, North Carolina, South Carolina, Vermont, and Wisconsin.

Granite has "chunks" of other rock mixed in kind of like a chocolate chip cookie with M & Ms. You'll typically find quartz, feldspar, mica, and hornblende folded into it. Granite is commonly used as a building and decorative stone

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