The markings on this pebble are entirely natural and exactly as found on the beach. Since I first found it, the white lines have remained unchanged but the dark colour of some patches has diminished with time. I have concluded that the dark patches were due to a damp surface film of microscopic algae or other micro-organism colonising those areas of the limestone with a coarser texture. These have eventually dried out and become inconspicuous.
White lines are wrapped around the pebble as if inscribed by an unknown artist, delineating curving abstract or geometrical spaces. Each angle of view reveals new aspects of the design. Pebbles with white lines and white patches on them are commonly found on the beach at Charmouth but this particular stone is astonishing in the intricacy of the markings. It is difficult to believe that the lines are natural but they are just the way I discovered them; they are a geological phenomenon and part of the petrology of the rock from which the pebble is derived.
Revision of a post first published November 2009
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Jessica's Nature Blog 
Fabulous rock!!
I have a few a bit like this but this is a splendid one indeed!
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When I first saw this stone, I was convinced that someone had decorated it. When I looked closer, I could see that the white lines were veins of quartz (?) in the limestone. It took a bit longer to work out how some of the patches might have acquired their darker colouring.
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Beautiful lines and shadings. I love how you’ve photographed the stone from so many angles.
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It was an unbelievable stone. I couldn’t get over the way that every change of angle revealed a new pattern.
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Thank you for sharing your great rock photos, and the information about the boring sponges. Beauty~Art.
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Thank you for visiting my blog. I am glad that you found the information useful and liked the images. I really appreciate your feedback.
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What a wonderful blog and pics. I have just discovered. I teach English in Spain in a High School and was looking for pebbles and rocks for my class blog. I wander if you’d mind my using a couple of pics , I would certainly cite you.
Thanks for sharing it.
María
http://1esoeiesramonllull.wordpress.com/
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Hello, Maria. I’m so pleased to hear that you like the blog and that you write a blog yourself for teaching English in your school. Yes, you may use some pictures of pebbles and rocks for teaching purposes – provided that you also give the source of the photographs as Jessica’s Nature Blog with a link.
Thank you for asking permission to use them. The pictures and text in my blog are actually copyrighted with all rights reserved – which means that they must not be reproduced in any way without specific permission being granted and certainly not for commercial gain. However, I usually grant permission for them to be used for teaching purposes if I am asked – as long as the source is credited.
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Hi – all the white material is CALCITE – no quartz at all. The argillaceous limestone bands shrink during diagenesis and calcium carbonate is precipitated in the joints. When the layers fall out of the cliff, they are broken and rounded by wave action to form these beautiful shapes.
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Thanks, Geoff. The information is gratefully received. It’s quite difficult for an amateur like myself to find out all I would like to know about the rocks I see.
Jessica
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