Fulgurite is a glass tube that is formed when lightning strikes the earth, especially in sandy soils or in areas where quartz is present. It can also be formed on the surface of a rock. Fulgurite is somewhat difficult to locate and hard to recover without breaking. Areas that are prone to lightning strikes are the best places to find fulgurite.
York County and parts of Adams and Cumberland counties all have many iron ore deposits near the surface. This can generate more lightning strikes, especially ground strikes, which could produce fulgurite. In searching eBay for minerals I have seen numerous postings of York County fulgurite! Several of my York county friends report that they live in areas that seem more prone to lightning problems than other neighbors, even right down the road.
Wikipedia has a nice write up on Fulgurite.
