Highrise enamel and gold, also known as Terzo Fuoco (three times fired - the enamel and the gold need to be fused on in seperate operations).
They indeed make this sort of work in and around Murano - but the largest producers are from the Czech Republic, notably Anton Rückl at Vcelnicka - but there must be a dozen others there as well. The difference between Italian and Czech produce is very hard to see, I think there are only stylistic indications not technical.