The Hexahedron Mine is located in the Hexi Mountains, it is accessible only by foot. The 2.5 mile hike takes you through a desolate portion of Pleasant Valley, very little plant life with the exception of creosote bush cover this part of the ancient dry lake. The trail leading up to the mine is rocky, and steep in places, nearly vertical for a short distance. From the road the views of the valley below are stunning.
Once you reach the mine there is a crumbling / roofless stone building. The stone building ruins are the highlight of the trip, the mines have been sealed by the Park Service, as usual they have decided that it is their position to keep us safe from potential harm.
Historical data on the Hexahedron Mine is scant, but like most of the mines in the Hexi Mountains it was likely worked between 1900-1930.
The following more technical details regarding the mine are taken from California Journal of Mines and Geology, Volumes 12-13:
Hexahedron Mine (Quartz) – It is 7 miles N.E. of Pinon Mountain. The shoot of ore lies on the side of the hill. It is 75 ft. long, 15 to 20 ft. in thickness, and dips 45 degrees north. The ore occurs as a mineralization of a felsitic dike, which strikes nearly E. and W. At the west end it is small (not over 4 ft.), but widens in going east. It passes from the south to the north side of the range of hills in which it occurs, and at the where gold was found, lies exposed along the hillside, the overlying rocks having been eroded. Dikes of dark green diorite, much decompsed at the surface, have been thrust into the felsite and adjoining rocks in a very irregular manner, and in this vicinity the felsite contains gold. A small amount of iron oxide, copper carbonate, and dendritic infiltrations of mangangese oxide are the only indications suggesting ore. The most ordinary rock, having nothing in its appearance to suggest that it is gold-bearing, is seen on closer inspection to be spangled with small points of gold. In the vicinity of the Hexahedron Mine are some smaller prospects, on which a few holes have been sunk. Ed. Holland and A.G. Tingmas, of Indio, owners.