Stage Centering: A Case of Trial and Error in Petrologic Evolution

Evolution in the field of microscopy has indeed brought to life many inventions and innovations that cater to a completely new world of demanding market and research needs. Among the many recipients and objects of such advancement, industrial science with all its tools, methods and equipment, always seem to have its hands full with the constant search and struggle for finding flaws and coming up with necessary corrective measures. As such, it is then touted to be always on the spotlight of the never-ending drama of the microscope’s ‘problem-solution-problem’ reality-based program. In this channel of microscopic issue, nothing could get more arduously and painfully real for a task wherein, despite the state-of-the-art developments and discoveries, even the ‘Big Brother’ of mineralogical microscopes or the crowd favorite of an interlaboratory petrology poll survey could solve the missing links in providing the recipients, both in the market and in the academe, a perfect and error-proof petrographic imaging instrument.

It is said that a petrographic microscope nurses itself some forms of limitations and imperfections. In order to fully carry out a competent and credible microscopic study, it should be a ‘given’ that the mineral fragment should not shrink small enough to pierce its microstructure diameter boundary of 0.010 millimeter. If such measure, however, is considerably short-handed, then it is expected that the performed petrographic microscopic study will do no good to reveal cryptocrystalline, amorphous materials or any small mineralogical bits of such miniature form. With these well-magnified handicaps, it is a ‘must’ then that utmost care and caution should be followed to fully appreciate the topmost operational potency of a microscope. Seasoned microscopists working on petrologic field of microscopes’ uses, strongly contend that it all boil down to proper knowledge in handling the petrographic microscope. In particular, these mineralogical experts pointed out on specific measures in centering the stage to ensure that the observer gets the desired microscopic image of the crystals that he desires. It was established that in order for the stage to be properly aligned in the set up, initial focusing must be started with a 10X magnification. This is done so because only at such magnification lens and capacity that further complicated and time-consuming centering adjustments are no longer needed. After which, petrographic microscopists suggest that the laboratorian must be able to locate the stage centering screws. These are recognized with their characteristic feature as actual screws or knurled knobs, and no extra care must be taken except for putting into mind that those should not be bumped for the centering will be lost. After which, it is advised that a distinguishable fragment of something exactly under the crosshair intersection should be placed as the petrographic microscope requires delicate stage rotation in such a way that the recognizable speck is as far as from the intersection as possible. Further adjustment in the stage centering screws is then needed in order to move the speck half way back to the crosshair intersection. To revert back the thin section, it is advised that it should be positioned in such a way that it is in nearest proximity to the crosshair intersection. Finally, proper centering of the stage is made by rotating it in such a position that it should be in the center of the described speck. If the stage, however, is still continuously observed to be rotating away from the crosshair intersection, then finishing touch is completed by repeating the procedure back from setting the speck under the crosshair intersection.