MicrobeHunter.com Microscopy Forum

There is a DIY tutorial online for a technique involving glueing a crystal grain to a needle and rotating it under polarised light. Does anyone know what this technique is called or even better, the tutorial I am looking for?

Haven't seen that tutorial but have seen several others concerning the use of petrographic microscopy, have a petrographic scope and have studied. Rotating a mineral grain or thin section under extinct polarized light and using certain filters is the major means of mineral identification. Look on YouTube. Subject is " Optical Mineralogy. "
Enjoy. Greg

The rotating needle, may be called the "spindle stage".

Thanks Patta. Thats what I was trying to recall.
For those unfamiliar, this system help. Someone shows how to make a home made one.

https://youtu.be/j955_cOi_qE

An extremely crude but effective implementation, to hold and rotate insects:
https://www.photomacrography.net/forum ... =43787

Decades ago, gluing a crystal to a rotating needle, such that its orientation in space was reproducible and defined along one of the crystal axes, was a standard technique of crystallography. The needle was mounted with plasticine (or similar stuff) to a simple goniometer head. Crystals were glued with shellac for example. Such operation was best done under viewing with a stereoscope (say, 0.7X-1X).