Just guessing....it has some of the outside characteristics.
I had wondered that, but I wasn't sure. I've never seen one outside of a rock shop...
It was definitely an odd find - what was weird was that there were quite a few of them in that area...
Flint or chert of some kind which are known to form as nodules in sedimentary rocks like sandstone and certain types of volcanic ash rocks. My guess would be flint due to the translucent appearance of the inner rock. As far as science can tell they form in a similar way to geodes but the nature of the crystalline structure is very different. cheers.
Cool - thanks for the info!
In my opinion, what you found is an agate geode; the hollow is probably tiny in the centre. Congratulations - the colour looks quite promising! You should have it split in two by a professional geologist and polish the cuts - you never know...
By the way, thanks for your vote!
Thanks for the vote as well!
I actually left the rock where I found it so others who venture up to this place could have a chance to discover it as well, so I guess we'll never know what it looks like inside!