A Student’s Guide to the Genesis of the Agates, Jaspers, and Opals

By: Donald Kasper

This short summary work is a high-level review of the following that the author has found in writing his major works on the agates, jaspers, and opals:

·         A concise definition of an agate, jasper, and opal.

·         A definition of a chert and flint, and their comparison to agates.

·         What is a chalcedony, and how does it differ from agate?  Hint: chalcedony is also banded.

·         12 major rules of agate genesis.

·         What went wrong with the European classification of the agates.

·         Agates are rocks formed in clay-silica systems.

·         Agates form as calcium-silica-hydroxyl gels.  It takes carbonate to make an agate.

·         The agates, jaspers, and opals are largely amorphous, not cryptocrystalline.