Re: Good reference book
A top notch reference on agates and jasper can be found at the compilation by Dr. Robert Pabian, a geologist at the University of Nebraska, Lincoln. His web site of terms is at:
I have had the opportunity and pleasure to use this source and, sitting on the 2/3rds of the worlds agates in the southwestern U.S., have offered up a number of clarifications to place name localities not in reference sources, and terms for agate/jasper species in the southwest where I rockhound. A large set of updates based on my correspondence with him have been recently uploaded.
The reason for place names is that the description of agates and jaspers is complex, and if people want to describe what they have, stating a locale is a good substitute if they don't want to use a long description. Generally, the appearance from many locales are distinct, so that a place name achieves the goal of describing the pattern and type of material collected there.
If you ever disagree with a term in the Lexicon, offer up yours and email it over to him. So far though, my changes or additions are where the rock definition or site location was not clear, and the Lexicon stated exactly that confusion. The complete answer is not always in the literature, so its interesting to be able to go to old described sites, see what is there, and pass it over the Dr. Pabian.
The Lexicon is a very thorough reference to all citations in the rock and gem magazines, books, and literature for every kind of chalcedony. It even shows terms used by dealer ads. You get to see what was the original meaning of the term when it was coined.
Hope this helps.
From Donald Kasper - November 16, 2007 at 16:06:13