The Spindle Stage
(Mickey Gunter, Geology, University of Idaho, with thanks to F.D. Bloss, last updated 5-Jun-96.)
The spindle stage is a single axis rotation device mounted on the stage of a polarizing light microscope. With it one can orient any principal refractive index direction of an anisotropic crystal into the microscopic stage and determine its refractive index and measure 2V, among other things. For an excellent discussion of the spindle stage see: Bloss, F.D. (1981) The spindle stage: principles and practice. Cambridge University Press.
This page contains information on the spindle stage. Several photos and videos are included. I also distribute several computer programs that are used in association with the spindle stage.
This page is being developed to be used by my students in optical mineralogy and in the Teaching Mineralogy Workshop
at Smith College in June.
My lab session for the Mineralogy Workshop deals with lab exercises and demonstrations based upon use of the spindle stage. They also explain how to build a poster board spindle stage.
The first draft of my notes can now be
viewed (html format) or
Different types of spindle stages, with a Swiss Army knife for scale. A Supper spindle stage is on top (available from Supper, Natick, Massachusetts). This type of spindle stage is used for research. In the front are two student models, the one on the left is a home-made cardboard version (thanks to Thomas Armbruster, Bern, Switzerland) and the one on the right is the detent spindle stage (available from McCrone Accessories, Chicago, Illinois).
Spindle stage videos
This following are videos made with the student spindle stage. To view the movies you must have a quicktime movieplayer installed for the Mac (just make sure Quicktime has been installed) or Windows 95 . (Movies were made with Fusion recorder on the Mac and converted with Movie Converter, 2 frames/sec, and compressed with Cinepak.)
- Short test video (57k).Try this before you move on to the crystals, it is shorter and will download much faster. This will help you debug your video player.
- uniaxial crystal A crystal of eudialyte with perfect (001) cleavage with its c-axis mounted perpendicular to the spindle axis.
- biaxial crystal A crystal of gypsum with perfect (010) cleavage and b=Y, with its b axis mounted parallel to the spindle axis.
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