This plate does not strike me as typically 19thC Murano, several small features seem at odds. I have been wondering if it could be Sowerby Venetian but images of so few examples are available for easy comparison. Cottle states in his book on Sowerby that both aventurine and trailing were used by Sowerby in their Venetian range.
Approximately 18cm (7") in diameter, fire polished pontil mark, 20 optic ribs (that do not show up all that well in these photos).
Those three features do not seem typically Murano (or Salviati) to me and neither does the blueish tint to the opalescence, any thoughts?
John