Known since the late 1800s, the thunder-egg beds near Del Norte, Colorado, have provided the collector in recent times with world-class plume and moss agate. Plume agate represents the ultimate in aesthetically arranged featherlike assemblages, whereas moss agate can manifest a bewildering variety of forms, including tubes as well as randomly intertwined fibers. These inclusions exhibit a wide range of color, from white to black and from brown to orange and red. Described as ...