Boulder Opal Microscopic Images

These images of boulder opal were taken through a Zeiss binocular microscope with a camera attachment.
The images were captured on Kodak Ektachrome transparency film.
Most of the images are of the one stone but at varying magnifications. Some of the images show no more than a pin head area of the stone.
I believe that I was the first to use this type of photography for commercial purposes. The images are more than 25 years old.