Maryland Green Marble Corporation Quarry (Cardiff Serpentine Quarry), Cardiff, Harford County, Maryland, USAi

Regional Level Types
Maryland Green Marble Corporation Quarry (Cardiff Serpentine Quarry)	Quarry
Cardiff	- not defined -
Harford County	County
Maryland	State
USA	Country

Quarry near Cardiff that produced serpentine for various uses, including ornamental Verde Antique. Operated by the Maryland Green Marble Corporation into the 1970s.

"A very large opening in serpentine (variety Verde Antique) over 200 feet deep is located at Cardiff on the Maryland-Pennsylvania State line. The Verde Antique has been removed in large rectangular blocks and used for ornamental building stone for which it is very famous. Minerals to be found in the surface quarries are antigorite, picrolite, williamsite, pyrite, malachite stains, chalcopyrite in small octahedral crystals, breunnerite, drusy quartz, chalcedony, calcite crystals, fibrous calcite, dolomite, actinolite, hyalite, talc, and dendritic wad."

From: Minerals of Maryland (1940) Charles Ostrander and Walter E. Price, Jr., Natural History Society of Maryland. p. 56

“Near the Maryland-Pennsylvania line a quarry was opened before 1900 to produce verde-antique ornamental stone. It has been maintained continuously since then, by various operators. Since the 1940's the operator has been the Maryland Green Marble Co., Inc., and the principal product has been "Cardiff green granito," or serpentine granules for use in terrazzo flooring. Currently (1956), about 90 percent of the total production is terrazzo aggregate; the other 10 percent is verde-antique ornamental stone for table and counter tops, fireplace facings, and other decorations. Serpentine from Cardiff is marketed throughout the United States and is exported. The company also sells irregular slabs for flagstone." (p. 56)

The verde antique is quarried from a channeled opening 247 feet deep, the present floor of which is 120 feet long and 60 feet wide. At a depth of 197 feet a platform leads from the quarry into extensive room-and-pillar workings, where the terrazzo stone is mined. The tunnels underground are about 35 feet wide and 40 feet high; roughly 40 percent of the total volume of rock is left as pillars. Two sets of joints in the serpentine one dipping about 45° and the other dipping 10° to 15° cause little trouble in mining or quarrying operations. Water accumulates slowly and is not a problem.

The verde antique is removed from the quarry in 14-ton blocks, which are then sawed to various thicknesses, sized, and polished. Serpentine for terrazzo aggregate is blasted out underground and then taken to the mill to be crushed and sized. The rock is not excessively hard, and therefore it crushes easily.

The serpentine at Cardiff is a streaked and mottled rock that ranges from light green, through emerald green to very dark gray- green, cut by numerous veinlets of white carbonate. Pyrite is fairly common. The pale-green variety, sold under the name of "Cardiff green," was once a popular decorative stone but is no longer quarried.”

Edited from Pearre, N.C., and Heyl, A.V., Jr. (1960) [see citation below] p. 717.

Host rock types: serpentinite
Geologic map unit: Wissahickon Formation; Metagraywacke

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Link to USGS MRDS:	10110571

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References