mid-century vintage Venetian Murano hand blown glass tiny liqueur glasses, black twist stems

Beautiful hand blown Venetian glass liqueur glasses, clear tulip shaped bowls with ebony black twist stems. No marks or labels on these, though I've been told they are mid-century vintage, 50s or 60s.

This is a lot of four glasses - two are 4" tall, two are 6 3/4" tall. All four glasses are in excellent condition without roughness or clouding.