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Virtual rocks, minerals and fossils for the Web: the colour scanner as an effective, cheap tool for direct imaging of geological materials.



Both authors in Dept of Geology, Oxford Brookes University when this article was written



Note: since the presentation of this talk over 20 years ago, the resolution of digital cameras has improved by orders of magnitude. Nevertheless, the scanner remains a useful tool for acquiring images of geological objects quickly, and without having to set up lighting (RJS, 14 January 2019).

Paper presented at Geological Society of America Annual Meeting, Toronto, 29 October 1998, in Session 169: T13. Creating Learning Environments with the Internet and Multimedia II - NAGT and AGI



Using a cheap scanner as a digital camera in the lab

scanner - 28 kb

the colour flatbed scanner is an invaluable tool for converting photographs and maps into digital format, so

a logical development was to scan flat geological specimens, e.g. sawn and polished rock slabs


Scanning flat rock surfaces

N.B. Harder samples can scratch the scanner glass. This may be protected by placing the sample on a thin glass sheet or transparent plastic sheet, or in a glass-bottomed container.

Thin sections and acetate peels

good for high contrast subjects
gives an overview of the thin section, often not possible with a petrological microscope with inadequate low-power objectives
experiment with backgrounds (white or black paper, mirror....)
try a slide scanner


acetate peel of 'coal ball' concretion with fossil plant material preserved in fine detail. Upper Carboniferous.

coal ball close-up - 30 kb

close-up view of fossil plant material in another 'coal ball' peel


Scanning 3-D objects

rocks with rough surfaces

Surprisingly, this too works successfully, giving a depth of focus of around 15 mm.

dudley slab - 106 kb

A cleaned-up bedding surface of Silurian 'Wenlock Limestone' from Wren's Nest, Dudley, West Midlands, U.K.



minerals - 25 kb
ammonite - 60 kb


a lot of detail can be seen, such as the sutures in this ammonite




loose sediments

scanner - 16 kb


in a transparent container, or a standard micropalaeontology mount, upside down:

slide mount - 4 kb 

or stuck to a card with double-sided tape

shell sand - 16 kb

Scan of carbonate sand from the Rockall Bank, NE Atlantic Ocean


Advantages of direct scanning


cheap, no film needed;

publication-quality images;

quick, simple macrophotography, with minimal training

for macro work, no need to set up lighting

bryozoan - 24 kb bryozoan - 22 kb

£100 ($160) scanner - first attempt

£600 ($1000) digital camera - after several attempts

Admittedly, this was written 20 or more years ago when we had just purchased our first, very expensive 1280 x 960 pixel digital camera. There have been rapid changes in resolution (and price!) of digital cameras. I would still contend, however, that for many purposes a cheap scanner will produce quicker, sometimes better images than an expensive digital camera with macro facility. [RJS, Jan 2019]
niagara - 24 kb

But you can't do this with a scanner!

(this is one of those 1280 x 960 images)

More advantages...


There are many possible uses of directly scanned rocks, minerals and fossils in teaching, learning and research, including:

web pages and paper handouts to support traditional and distance learning

e.g. sedimentary petrology (scroll down to the section on Porosity)

replacement of published materials, which can no longer be used as multiple class copies because of copyright restrictions

labelled trilobite - 41 kb

e.g. labelled diagrams of fossils, for web pages or printed class handouts.


labelled images to help students know what they should be seeing through the hand lens or microscope (useful for beginning students or subtle features). e.g. "Can you see the two cleavages at 87 degrees that I'm trying to point to as you look down the hand lens? (But actually I'm blocking the light, and the object I'm trying to point to is not the same as the one you are looking at!)"

labelled granite - 35 kb

If the student looks at the sample at the same time as viewing a magnified, labelled image on the computer (e.g. in a web page), small and subtle features are more easily explained and understood.


More uses...

amber - 48 kb

overcoming the problems of

having only one good sample for a large class

access to rare or fragile specimens

24 hour and remote access

rapid production of images for publication;

rapid exchange of 'virtual samples' between students, teachers, research workers, either privately or on the Internet (e.g. getting expert to identify a sample)


Other materials

Of course, this technique is not restricted to geological samples. The possibilities are limited only by our imagination. Some examples:

tree rings - 7 kb banana - 5 kb

tree rings

connector - 4 kb

 In conclusion

scanned rocks, minerals and fossils can never be a replacement for the real thing

however, alongside natural materials they may play a valuable role in helping students to understand those materials

stromatolite - 27 kb

polished surface of planar stromatolite, Lower Jurassic, Boutenac, Aude, S France


This page is maintained by Roger Suthren. Last updated 14 January, 2019 4:15 PM