From amos.brad@gmail.com@21:1/5 to All on Mon Nov 21 18:31:20 2016
I used to have a slide consisting of a thin fragment of a mineral with very distinct cleavage lines in only one direction, running right across the field of the microscope. When the fragment was rotated to maximum darkness between crossed polarisers, the
eyepiece cross-hairs could then be set accurately parallel to the cleavage direction, which then corresponded to the analyser axis of polarization. I have lost this slide and would like to obtain a replacement. Does anyone recognize what mineral it was?
It could have been a rock section or a cleavage fragment, probably the former. I would be most grateful to know. I think it was a Zeiss or Leitz slide with the specimen in a metal plate mount.