Book Review Gems & Gemology, Fall 2014, Vol. 50, No. 3

Books: Kentucky Agate:
State Rock and Mineral Treasure of the Commonwealth

Kentucky Agate: State Rock and Mineral Treasure of the Commonwealth(ケンタッキー州産アゲート:州の岩石そして鉱物の宝物)
By Ronald L. McIntosh and Warren H. Anderson, 216 pp., illus., publ., by University Press of Kentucky, Lexington, 2013, US$45.00.
From rough found in the streambeds of Station Stamp Creek to finished jewelry, the story of Kentucky agates, the official rock of the Bluegrass State, is told in words and shown with beautiful images.

The adventure starts in the first chapter, which offers 10 examples of agate types with descriptive names such as plume, moss, cloud, and flame. The photo meant to show moss and dendritic agate is not a good example, though, as the image did not clearly resemble moss on a rock of the branches of a tree, as described.  

Chapter 2 explores when and where to find agates, as well as places where collecting is not permitted, such as Daniel Boone National Forest or the Natural Bridge State Park and River Gorge Geological Area, both of them scenic and popular spaces. Maps and photos of these locations are provided. The chapter also provides the names of gem and mineral shows, both within and outside the state, where agates are sold, as well as Kentucky colleges and museums with collections that are open to the public.

The formation and geology of agates are covered in the next two chapters. Chapter 3 features 16 photos of polished material, with captions describing the incredible colors and unique features of each sample. Chapter 4 includes a geologic map of the area where most Kentucky agates are found, along with the origins of their beautiful colors and banded patterns.

Microscopic features are described and shown in chapter 5. Under magnification, the causes of the unique features are more easily seen, and the captions offer additional details. For example, page 40 features an agate with heart-shaped banding, yellow limonite, and red hematite spherical inclusions. Ten of the samples are shown in reflected light, two in transmitted light, and another two in both reflected and transmitted light. The differences in appearance are striking, though it is unfortunate that the captions don’t list the magnification used.

The highlight of the book is chapter 6, featuring 255 photographs of cut specimens and slices. There are no more than two agates per page for over 149 pages. The backgrounds have been removed from the photos so the agates are seen against the white page, which makes the beautiful colors, patterns, and features even more breathtaking.

The final chapter features 11 examples of agate jewelry, with a photo displaying various agate cabochons. There is a refreshing mix of the traditional belt buckles and bolo ties alongside some very modern designs. One notable example is a tie clasp featuring a freeform polished agate with bold, contrasting colored bands of red and gray/black designed and created by Rachel Savané. Additional works are listed in the bibliography for readers interested in more information.

In this volume, Ronald McIntosh and Warren Anderson bring together an amazing collection of agates, professionally photographed with high-quality printing, creating a greater level of appreciation for these natural works of art.

Douglas Kennedy is an instructor of gemology at GIA in Carlsbad, California.