Agate from East Timor.
"Agate" is a rockhound/collector term for irregularly- & concentrically-layered masses of microcrystalline quartz. Individual layers consist of translucent or opaque, microcrystalline, fibrous quartz called chalcedony. Impurities in different layers cause variations in color. Many agate masses are simply geodes that have completely filled up with quartz. Common agate colors are clearish-whitish-grayish, brownish-red, and yellowish-brown. Commercial agates that occur in greens and blues and purples are almost always dyed (faked).
Tags: agate East Timor chalcedony quartz