User blog comment:DogDays124/New Test/@comment-2047157-20101206220734

Meh, why not?

Marble is igneous which is formed by cooled magma.

Kimberlite is sedimentary which is formed by tiny sediments glued together by pressure.

Coal is metamorphic which is the result of intense heat and pressure.

Value? I doubt that is relevant in geology. Anyway I don't know.