marbles are not hand blown..they are taken from a glory hole and rolled but its if they were blown they would be hollow...they do have pontils some many different kinds..crease..point pontil rough pontil polished pontils...etc...theres just about as many presentations as there are collectors...aboiut everyone would have different takes....i would not take one collectors revelations as gospel as many ideas have been discredited and some things are downright impossible...marble collecting has elvolved in the last 20 years ive been in it....and when i first started i can think of many,many ,theories that have been didproved...