Mineral Identification

I offer mineral identification services using physical testing combined with optical analysis including use of petrographic microscopes.

Two Leitz Ortholux Microscopes


Polarized Light Microscopy or PLM

The petrographic microscope, which uses polarized light to reveal optical properties of minerals, is one of the basic tools of investigation of optical properties of minerals.  It allows determination of refractive index, birefringence, and other properties.  It is quick and more economical analytical technique than other methods.  I combine PLM with dispersion stain (or focal mask screening) to rapidly and accurately determine refractive index.

Spindle Stage Analysis

Minerals are three dimensional objects and their optical properties visible change depending on your point of view.  However we view minerals with a microscope on a flat, two-dimensional stage, which limits our ability to fully appreciate the complexities of a mineral.  Ray Wilcox (U.S. Geological Survey), Donald Bloss (Virginia Tech), and Mickey Gunther (University of Idaho) developed and perfected equipment and techniques using a spindle stage, something I call the “third dimension in mineral analysis”.  The spindle stage allows rotation of a tiny mineral grain to provide views of all optical properties of minerals.  I have had the honor of meeting Ray Wilcox and the good fortune to take classes from Gunter and Bloss. Spindle stage analysis is a powerful analytical tool used in the Focal Point Mineralogy lab to study unknown minerals.Photo collage of various aspects of spindle stage analysis