This is an unusual piece, I've classed it as a nodule, due to its shape, likely some sort of 'plug' formed in a sea creature's evacuated hole, but there isn't the usual white covering, only on the top, which is smooth and flat, and where there is also the hint of a small area of Quartz or Chalcedony. A bit of a curio which also looks like a dragon...

Please see photos for size guidance

Weight 29gms