Blue Goldstone - like it's cousin - the regular, bricky-coloured Goldstone is glass - with metallic flecks suspended in it.
It reminds me of the line from 2001: Space Odyssey, where - when confronted with the monolith in space, that is actually a portal - he cries, in wonder - "It's full of stars!" If the movie left you baffled, by the way - the book makes much more sense.
Goldstone is also known as aventurine - not to be confused with the natural stone called aventurine.
Lampworkers also use goldstone in beadmaking, and it is also used in handmade marbles, where it is known as "lutz." However - we don't suggest melting these beads down to use in your lampworking, as the COE may not match your glass.