Dimension stone (Mt. Airy)
Geology

Detail of polished slab of Mt. Airy 'granite,'  Coin is about 19mm in diameter. 

Location of  the Mt. Airy 'granite' (orange square) in Surry County, NC. Click here for a larger image of the same view; use the back arrow of your browser to return to this page.


Granite was designated in 1979 as the official Rock of the State of North Carolina. 

'Granite' is quarried extensively at Mt. Airy. Technically this rock is a leucogranodiorite. It  is white to light-gray and is composed of quartz, plagioclase, microcline, biotite and accessory minerals (magnetite, monazite, apatite, and sphene). Dietrich (1961) provides additional detail on the petrology and mineralogy of this rock. Click here to view a more detailed map showing location and geology.

The granite body is roughly circular in shape with a diameter of five miles. It underlies the City of Mt. Airy and the surrounding area in Surry County, NC (lower left). The only dimension stone company using the stone is the North Carolina Granite Corporation.

Its color and texture are remarkably uniform throughout. The uniformity of the color and texture permit the repair of damaged monuments even though they were crafted decades ago. 

Tests on the Mt. Airy granite show that a cubic foot weighs 165 pounds, and its crushing strength is 29,233 pounds per square inch.

The stone is quarried from a large open-face quarry (below). 

Aerial photo view of Mt. Airy quarry. Photograph shows the scale of the quarry. The buildings in the upper center of the photograph house various stone dressing operations. Details of these are shown in the following pages. Despite over one hundred years of dimension stone production, only now has the quarry reached the general elevation of the surrounding land. This photograph was taken in 1993.