Press Announcement: Release of “A Field Guide to the Agates, Jaspers, and Opals, Volume IV, A Microscopy Study of Banded Agates and their Structures,” 2013, 265 pp., by Donald Kasper. The book is color printed, spiral bound. The book retails for $95.

I am pleased to announce a major work dealing with the banded agates and their structures, which includes a polarizing microscopy study of structures, classification of agate banding systems, and study of their microstructures.

This book studies for the first time all of the structures found in banded agate systems. It includes a classification of the 35 types of banding systems that occur in silica rocks. It includes a microscopy study in plain and polarized light of their structures. For example, did you know there is no such thing as chalcedony versus agate? In polarizing microscopy, there is clearly a continuous blend of banding, granular, oolitic, and mosaic quartz structures in all possible combinations. Many agates are not solid fibrous silica, but only have it here and there in bits in specimens. What do we call those? Agates. Of course, they are really blends. Sedimentary agates are oolitic cherts that blend into agates here and there in places in specimens, so I document the chert-agate rock species in this text.

The book covers a comprehensive look at structures defined best by considering agates to be formed from a gel state. The book covers all of the tube structures variously interpreted as tubes of entry or tubes of escape, and makes the argument though a large set of examples not found in popular literature, that they are tubes of escape. The book covers several types of silica banding systems not covered in textbooks, in particular a study of the chevron agates, which are not wall-banded. Complex structures found in banding systems ignored in scientific and popular literature are thoroughly covered.