Just about anybody who lives in California, and many others who don’t, know about Devil’s Post Pile Park located on the west side of Mammoth Mountain ski area. It is a spectacular west-facing wall of basalt columns several feet wide rising 60 feet straight up. When I visited there in 1999 one scary fact impressed on the casual trekker by a Park Service sign was that the whole thing was earlier on considered a nuisance and a prime source of building material for a dam on the adjacent river for gold mining purposes or some such. The whole display of the post piles is large, but well within the purview of the visitor, so obviously this site could have been easily destroyed. As much as I wanted a rock sample I realized it would be totally inappropriate to take a piece of this magnificent structure! Not to mention that the very smallest samples would have weighed in at a significant fraction of a ton!
Much to my surprise and delight then, while shopping for flagstone pavers at the local rock and brick construction supply yard, I spotted a box labeled: “Small columns,” and inside were fragmented pieces of columnar basalt, supposedly from Washington State. I was able to find a nice piece for my collection, a few inches long, see photo. Notice it has four well developed faces that could be extrapolated out to give six faces total, although since columnar basalt is not a single crystal, the number of faces are not determined by crystal structure considerations and it could possibly have only 5 faces. Plus one end has been broken off showing the basic mineral structure and the other end has been roughly sawed showing a cross section view.
No comments:
Post a Comment