Virginia State Seal

Virginia Department of Historic Resources

Greenstone



Greenstone, Afton Mountain, Nelson County, Virginia.

Type General

Collection Location:
Catoctin Greenstone metabasalt from the Swift Run area in eastern Rockingham County, and at Afton Mountain in Albemarle County, Virginia

Description
Greenstone is metamorphosed basalt; dark green in color when freshly broken, weathering to a greenish brown. Greenstone may contain quartz and feldspar, as well as rusty colored, weathered cavities that represent vesicles through which gases escaped from the top of the lava flow that formed the section. Texture is typically fine grained and the darker the color, the more fine grained and harder the material. Poorer quality material breaks and shears easily and has been called catoctin ‘schist.’. Found in situ in massive cliffs. It is also abundant in cobble form in the streams draining the Blue Ridge to both the west and the east. Also know to contain feldspar, epidote and veins of jasper in counties to the northeast, like Greene County.

Distribution
From central Pennsylvania in a southwesterly direction through the central part of Virginia. There are two main belts of outcrop; at or near the summit of the Blue Ridge, and at the border of the Inner and Outer Piedmont.

Cultural Implications
Used throughout prehistory, primarily for heavy tools manufactured from oval-shaped cobbles (chipped and bifacially worked large pieces, hammerstones, ground stone axes and celts). Occasionally broadspears from the Late Archaic were made from greenstone. Nash has noted Early Woodland point forms manufactured from greenstone in Madison and Greene counties. Late Woodland agricultural hoes are commonly made from the either the large curved exfoliated or flaked spalls of greenstone.

References

Prepared By Nash 1999; Egloff 2008