This is "Snowflake", "Opalina Fiorentina" by Stelvia, Empoli glass. I have seen its design attributed to both Wayne Husted and Carlo Moretti. I've sought a clarification from Wayne Husted's website which has an interesting account of his time with Stelvia that discusses and illustrates his "Antigua" range from the early '60s and how it was made. "Antigua" did not include this design.