Welcome to Geosec Slides

A resource for geologists, amateur and professional, to aid the study and identification of rocks minerals and fossils.

Geosec Slides is pleased to announce a new site for the sales of Thin Section Microscope slides for amateur and professional geologists


Payment is through Paypal. Credit and debit cards are accepted and it is not necessary to have a paypal account, and there is no need to register with Paypal.
You will be asked for your address as this is required for correct dispatch. 


The websites www.geosecslides.co.uk and www.geosec.biz will be retired during the course of 2019. Their contents, as far as possible, will be moved to the new website. This will take some time, there is much to transfer, and the work will have to be done when I am not busy making slides. 

Thin Section Microscope Slides of Rocks and Fossils

Geosec specialises in the production and supply of thin section microscope slides used as one of the two main methods of rock classification (the other being chemical analysis). Viewing thin section slides enables the geologist to identify the constituent minerals and textures of the rock. This, with information gathered from the site of collection, provides evidence of its chemical composition and the manner of its creation.

The slides reveal fascinating and beautiful internal structures, opening a window to parts of our world normally invisible. View through a microscope a hidden universe of colours and shapes, spectacular and intriguing, even without specialist knowledge.

What is a Thin Section?

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It is a slip of rock, mounted on a glass microscope slide, and ground very thin. 30 Microns is the ideal thickness. (A standard piece of paper is 100 microns thick) At this thickness virtually all rocks are transparent, and the individual minerals that make up the rock can be seen and identified. When viewed through a polarising filter interference colours can be seen, a similar effect to oil on water. This too is used as an aid to identification.

Study of thin sections is a part of nearly all higher level geology couses, and experience in mineral identification is gained by viewing as wide a range of thin sections as possible. Geosec offers a large selection of slides from localities worldwide.