Microscopes do not just have to be used for biological specimens. Today, I used my Zeiss IM35 microscope to look at thin sections of a meteor and meteor impactite – the latter is the rock around the site of a meteor impact.
Polarized light waves are light waves in which the vibrations occur in a single plane. The process of transforming unpolarised light into polarized light is known as polarization. There are a variety of methods of polarizing light (www.physicsclassroom.com/class/light/Lesson-1/Polarization)
The meteor views should chondrules – these are areas of crystal formation believed to be created early in the solar system formation and can be seen as round inclusions within the meteorite structure with internal crystalisation (square structures).
The impactite shows rock crystals (square shapes) in a more diffuse matrix – the latter is composed of glasses – molten rock (now solidified of course) as the result of the energy realised by the impact. The crystals within the glasses represent areas of the rock that did not melt, perhaps due to a different chemical structure with a higher melting point.
I then tried hand-holding a single linear polariser under the condenser (the lens that focuses light from the illuminator on to the slide) and twisting it to see what effect this created. Different crystals (formed from different chemicals) bend light differently and this changes the coloured pattern seen with the polariser and hence this technique can be used to identify what the chemical components of the rock are – but don’t ask me what my images show! I don’t know! Polarising microscopes in professional labs use crossed polarisation which involves a linear polarising filter bother before and after the specimen – I am still thinking of a way to add the second polariser to my set up.
All following images were taken using Zeiss IM35 microscope, 20W LED www.retrodiode.com illuminator (I needed the extra light especially when using the polarising filter), hand-held 55mm linear polarising filter under condenser, 3.2mm and 10mm objectives, Bresser MikrOkular camera.
In future posts, I hope to be able to image these specimens in crossed polarised light.
Microscopy Chondrule rich unclassified NWA meteorite (from North African Sahara desert in 2016) 29/06/2017
Chondrule-rich-unclassified-NWA-meteorite-Sahara-Desert-2016-10x-objective-plain-light-290617-details-of-chondrule-structure.bmp (below – this is the same field of view as the following pictures with a polarising filter):
Photos of microscopic images of thin sections of impactite
Gardnos-Impactite-3.2x-objective-white-LED-light-290617II-showing-glass.bmp (below – glass is black amorphous material between crystals):