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We found this today in Acton CA USA. Would like to know what it is.

enter image description here

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    $\begingroup$ Please read this guide on how to ask rock identification questions and edit your question to add more information. $\endgroup$ – bon Jan 28 '18 at 19:11
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    $\begingroup$ Is it possible for you to post a picture looking into the stone from the flat side on the right of the photo you posted? This could be quite interesting. Please also see the guide on asking identification questions, above. Do you have a piece of quartz crystal? can you scratch that flat surface with it? Will it scratch a piece of quartz? $\endgroup$ – haresfur Jan 28 '18 at 23:22
  • $\begingroup$ quartz again XD $\endgroup$ – user12525 Jan 21 at 0:25
  • $\begingroup$ what is the size of the rock,and please add the other details too. $\endgroup$ – trond hansen Mar 26 at 6:34
  • $\begingroup$ Thank you all for your suggestions. I've got so many rocks to figure out now, I'm setting up a little workshop so I can do these tests. Thank you. I'll ask with more detail next time. $\endgroup$ – Cece Smith Apr 5 at 19:31
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From the photo, your stone is appears to be chalcedony, a form of quartz. This is based on texture and its translucency.

It is possible your stone might be something more unusual given its location but you need to determine hardness and density:

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    $\begingroup$ My problem with this answer is that there appears to be a flat cleavage face on the right. It's hard to tell from the picture but I was thinking it looked like a single crystal rather than a cryptocrystaline mass. Need a few more photos to tell. $\endgroup$ – haresfur Jan 30 '18 at 21:52
  • $\begingroup$ To me, the face looks like an elongated fracture like the type often seen with chert or flint. I agree it might be something other than quartz. $\endgroup$ – Gary Kindel Jan 31 '18 at 13:17

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