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Rock is fairly crumbly but takes force to break bits off. Found along the river Severn at Portishead battery point in the uk. One side looks like could be fossils and the other side interesting crystal looking bits some of which are cone shaped. It’s my daughters special stone so anything u could tell us would be great. She’s 5

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  • $\begingroup$ +1 For the well written question with daylight pictures. $\endgroup$ – Jan Doggen Aug 7 '18 at 14:10
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The image below is of a specimen collected from the Portishead-Clevedon area of Somerset now housed at the Bristol Museum. As JulPal mentioned the crystals do look like calcite, but to be sure you can try to scratch them with a steel nail or knife. If the steel scratches the crystal then it is likely calcite since steel is harder than calcite (calcite=3 & steel~4-5 on the Mohs hardness scale). The pointed crystal are sometime referred to as dog tooth calcite and have a scalenohedral form. To me, the fossil on the back of your specimen looks like a piece of a brachiopod shell.

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Source: http://www.hullgeolsoc.co.uk/mikcolport.htm

Unfortunately this image isn't labelled, but scanning through those listed on the provided line I'm wondering if they aren't calling it a calcite mudstone (I39).

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    $\begingroup$ The BGS's iGeology App lists Battery Point itself as "Mercian Mudstone Group" (Marginal Facies) - Conglomerate. Triassic 200-251Ma, shoreline deposits. Of course as you found it on the bank of the river, it could be from nearby rather than the Point's bedrock. $\endgroup$ – winwaed Aug 7 '18 at 14:44
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These are calcite crystals. The fossil is a gastropod (snail) possibly Pleurotomaria.

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