Geodes are popular items among rockhounds. They are openings in rock—commonly limestone or volcanic ash beds—that have become partially filled with minerals deposited from deep fluids. The usual minerals lining geodes are calcite or quartz. This gallery shows examples of both. Dolomite, pyrite, opal, celestite (strontium carbonate) and other minerals are also known in geodes.
Images 1-9 of 9
 Calcite Geode |  Geode Exterior |  Geode Fragment |  Calcite Geode Lining |
 Dogtooth Spar |  Dogtooth Spar Closeup |  Quartz-Lined Geode |  Rock-Shop Geodes |
 Inside the Rock-Shop Geodes |
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