I believe it to be Crystal Glass ~ a bright ping when you tap it.
Vintage Cobalt Blue Glass Bottle Heavy Thick Glass Blue Bottle 10” Tall
Cobalt Blue Glass Empoli Blue Glass Brandy Snifter Vase Vintage
Vintage Retro Cobalt Blue Glass Posey Bowl Trinket Bowl Blue Art Glass
Cobalt Blue Glass Bell Bristol Blue Style Victorian Inspired Clear Handle 5”
