specially concurring.
I concur in the result only, preferring that we simply hold that gravel is not a mineral. If lands being conveyed are known to be valuable for gravel, such can be retained, if the parties so intend, by specific reservation of gravel in the instrument of conveyance. The same is true if there is no knowledge of the existence of gravel. In the absence of such reservation, gravel is not reserved. The benefit of such a holding is that it is simple, clear, without ambiguity, and easily applied. It would eliminate litigation over this seemingly troublesome question.