A scientific cross-section illustration of a purple geode revealing intricate quartz crystal formation architecture, concentric agate band layering, drusy crystal cavity, and iron oxide mineral pigmentation within the hollow sphere on aged cream paper, handwritten geological annotations describing each crystallization phase and mineral deposit sequence, measurement scale in centimeters along the edge, soft museum spotlight from upper left casting delicate shadows, museum archive quality, Pantone-accurate deep amethyst purple crystal terminations with ivory quartz druse highlights and burnt sienna iron oxide vein tones, composition centered to showcase the geode's natural hollow cavity architecture, mood: geological precision capturing Earth's underground crystallizing wonder, hyperrealistic details of crystal facet textures and agate band rhythm visible