Chalcedony
See Chalcedony Varieties for specific types including agate, onyx, heliotrope, and more.
Parent: Rocks & Minerals
Chalcedony is microcrystalline quartz that includes agate, jasper, onyx, and related varieties; it typically forms from silica‑rich fluids filling cavities and fractures.
┬─┬ノ( º _ ºノ)