This piece of Chalcedony was part of a handful of agate slices which one of our founders brought over ot Scotland from Germany back in 2020. This resulted in these slices hanging around the rock room ever since. Some have been sold rough, two were hand polished and sold, and there are chunks still left on our site to this day.
This piece has been polished after I got sick of it hanging around the to-be-polished drawer and smashed it up with a hammer. I put the pieces into the rock tumbler and polished them for a month through different grit stages, polishing powder, and soap cycles to clean it up.
This is a blue chalcedony, which you could call grey, with a slight skin still on it where the outside of the rock is. It's so satisfyingly smooth that it makes me want to carry it around and just feel it. Any other neurodivergents out there looking for a fidget stone will love this. 
Also its chalcedony, microcrystalline quartz. Crystal healers love this material particularly because there are not many unusual blue stones for that throat chakra.