leaverite
n.— «I always carry a rock hammer and a gunny sack, and when I see a likely piece of jasper or agate, I chip a corner to see how it holds up. Like as not, the whole stone may shatter making it into leaverite (leave-‘er-right there where you found it).» —by Eliot Wigginton, et al. Foxfire 5 June 1, 1979. (source: Double-Tongued Dictionary)