| shale | 1. A shell or husk; a cod or pod. "The green shales of a bean." 2. [G. Shale. <geology> A fine-grained sedimentary rock of a thin, laminated, and often friable, structure. Bituminous shale. See Bituminous. Origin: AS. Scealy, scalu. See Scalme, and cf. Shell. Source: Websters Dictionary (01 Mar 1998) |
|---|
| alum shale | <chemical> A variety of shale or clay slate, containing iron pyrites, the decomposition of which leads to the formation of alum, which often effloresces on the rock. Source: Websters Dictionary (01 Mar 1998) |
|---|