From Conservapediamineral aggregate is a rounded, hollow nodule, lined with crystals, usually quartz or calcite. Amethyst is an example of a mineral exhibiting a geode form.
Young Earth Creationist View
The secular explanation of geodes is that calcite concretions formed around decaying organic material, and that over thousands of years, these concentrations were replaced by quartz. Since there has not been enough time since the creation of the Earth for this to happen, creation scientists theorize that geodes were created in their present form.
- ↑ Chesterman, Charles W. The Audubon Society Field Guide to North American Rocks and Minerals, Alfred A. Knopf: New York (1987) p. 40