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Hi,
I found this rock (fossil?) on the south coast of the Isle of Wight.
It is perfectly round, about 7 cm in diameter and very heavy.
Can you tell me if this is fossilised wood or something else?
Regards,
Roufmeister
That makes sense - it may have come from the Chalk capping the adjacent hills - yellowish on the map above.
Can you clean it up somewhat - it may be a mudstone concretion instead. Can you weigh it to the nearest gram and measure its volume in ml/cc by displacement in water using a measuring jug or digital scales (http://www.johnbetts-fineminerals.com/jhbnyc/articles/specific_gravity.htm)
Thanks
That gives a very approx density of 2.8. Any chance you can improve on the volume estimate using the method in the above link? Pyrite/marcasite is 4.8-5 so you probably have a ferruginous mudstone concretion from the Lower Cretaceous Lower Greensand Ferruginous Sands Formation instead. - photographs are never as good as having the specimen in one's hand!
Pyrite/marcasite can oxidise to a dull rusty colour and lose the crystal shape and colour but still with a radiating texture - it was this thought and the shape which led us to the first suggestion - hence the need for the additional info. you have provided.
You can find Chale in the Southampton link above by Edit>Find on this Page> Chale
Good idea - Angela Marmont Centre - might be worth emailing them first with the link to this thread: http://www.nhm.ac.uk/natureplus/message/116253?fromGateway=true&fromGateway=true#116253