Generate a dark fantasy rocky forma...

Generate a dark fantasy rocky formation that fits within a 128x128 block area. Create aggressive jagged cliffs with sharp rock spikes pointing outward horizontally rather than upward. The formations should surround an open center area about 75 blocks wide, forming an irregular natural ring (not a perfect circle). Style should feel harsh, hostile, and dangerous. Color palette: gray and amethyst tones using deepslate, cobbled deepslate, basalt, tuff, and amethyst blocks.