I picked out these five white nodules because we find more of these than anything else. These five pieces have potential. The largest piece looks like quartz teeth. The second largest oblong looks like it may have white eyes under the skin. I would recommend tumbling. The large round one has lines on one edge. I'm guessing there's a patch of onyx. 
The smallest one looks like an agate bubble inside another bubble. The last stone also looks like the dappling might be eyes.
These nodules are perfect for home cutting, lapidary crystals, or for home tumbling. They even make lovely examples of nodular Scottish crystals.