Archivo: Agate-filled geode (Brazil) 2 (32714553426)

Descripción: Agate from Brazil. (public display, Carnegie Museum of Natural History, Pittsburgh, Pennsylvania, USA) "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). The whitish, glassy material at the center of this specimen is macrocrystalline quartz.
Título: Agate-filled geode (Brazil) 2 (32714553426)
Créditos: Agate-filled geode (Brazil) 2
Autor(a): James St. John
Términos de Uso: Creative Commons Attribution 2.0
Licencia: CC BY 2.0
Enlace de Licencia: https://creativecommons.org/licenses/by/2.0
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