A Field Guide to the Agates, Jaspers, and Opals
Volume III--A Study and Classification of
Microstructures, Banding, and the Clays
By: Donald Kasper
This is the first comprehensive book of agate, jasper, and opal microstructures. This book is 192 pages. It book contains over 300 photos of microstructures and inclusions in the agates, jaspers, and opals. It classifies over 275 structures; over 60 are new that the author assigned names. They are all classified by their structural and compositional type. Special emphasis is paid to the clays and chlorites represented in the agates. Electron micrographs of the clay minerals where they form distinctive structures are correlated to the clay inclusions found in the agates. A classification of the 24 types of banding structures with representative photos are also included
Tubes of clay with adsorbed green chlorite are surrounded by quartz crystal layers
in a background of clear silica (agate). This is in a Frieda, Oregon thunderegg.