A visit to Woodlawn Quarry is suitable for ages 10 to adults and provides an interesting opportunity to observe common mineral specimens, identify the quarry as an early mining site, appreciate the physical work necessary to quarry rock with hand tools, and discuss the economic importance of the minerals found in the quarry. The minerals that can be readily found and identified in the quarry are feldspar, quartz and mica.
This area was bought in 1910 by William Bancroft as a wild flower preserve. It is now part of the First State National Monument, a Federal National Monument within the National Parks System.
Feldspar was actively quarried at this site from 1850 to 1910. There were many feldspar quarries or spar pits as they were commonly called scattered throughout the Delaware Piedmont in the early eighteen hundreds. The feldspar recovered from this spar pit was transported by horse and wagon to a factory in Philadelphia where it was used for making porcelain products such as dishes, figurines, false teeth, or sinks. The quarry eventually closed because machinery made other sites more accessible.
The rock quarried is an intrusive igneous rock called a granite. Intrusive rocks do not flow or explode from a volcano onto the earth's surface, but solidify deep within the earth. Molten rock called magma flows slowly through cracks or other zones of weakness in the local rock and cooled slowly to solidify into a rock made up of large mineral grains. The intrusive rock quarried here at Woodlawn names a graphic granite because the feldspar grains contain inclusions of quartz in geometric shapes that look like the cuneiform writing of the ancient Arabs. The graphic granite also contains white mica (M