Contents

Overview of Agate and Geode Genesis. 4

Part I.  Historical Background. 4

The Great Empire Studies the World. 4

The Age of Dana—the Model of Agate Genesis is put Forth. 6

The End of the Age of Minerals. 6

Part II.  Agate Genesis Basics. 8

What  is an Agate, Jasper, Opal, and Chert?—The end of Cryptocrystalline Quartz. 8

Agate is a Rock; The End of the Age of Florke. 10

The End of the Age of Heddle. 11

The End of the Age of Roedder--Silica Gels form in Geologic Systems. 14

Part III.  Volcanic Ash Systems. 16

Whence Cometh the Volcanic Ash. 16

The Work of Heaney--The End of Magadiite. 18

Part IV.  Studying Inclusions and Banding to Study Agate Genesis. 21

Our Agates are Full of Clay!  The World of Morphologies. 21

How Did the Inclusions Form?  The Clays. 24

How Did the Inclusions Form?  The Zeolites. 25

How Did the Inclusions Form?  The Carbonates. 26

What Makes an Agate Banded?. 27

What Makes Banded Agate Tube/Dilation Structures?. 30

Part V.  Geodes and Amygdules in Volcanic Systems. 34

Lava Host Rock Role in Agate Formation. 34

The Formation of Lithophysae (Geodes, Thundereggs, Amygdules) in Volcanic Systems. 37

Geodes Don’t Form in Ash--The End of the Age of Ross and Smith. 38

Geode Crystalline and Geode Aqueous Structures. 39

Agates and Geodes in Supercritical Systems. 40

A Classical Geodic System.. 41

Agate in Vein Systems. 43

How Lava is Made Revisited--The End of the Age of Bowen. 46

Part VI.  Review.. 49

Part VII.  Geologic Systems with Agates and Geodes. 50

Where do we Hunt for Agates?. 50

Where do we Not Hunt for Agates?. 51

Help!  I just realized all agates do not form in lava voids! 51

General Discussion of Inclusions. 53

Banding Systems. 56

The Limitations of X-ray Spectroscopy. 60

Kasper Jasper Press Titles. 61