Outcrop of quartzite in the form of polygonal columns as found in Maktesh Ramon, Negev Desert, Israel. At first sight any geologist would mistake this rock for basalt, a rock that commonly, and quite uniquely for that matter, occurs in columnar form. Basalt is volcanic rock, and the polygonal columns result from shrinkage-adjustments during cooling and solidifying of the lava. In the case of this columnar quartzose sandstone something else accounts for their formation. Hydrothermal processes involving influx of superheated water from nearby intrusions have been hinted at by some scientists.