That's the £1 million question...
Aqualux is only dated to 1939 and had a very, very short production life, whereas 'Antique Tinted' (I note Andy McConnell calls this "Carnival" but I need to confirm this with him*) was produced sometime in the 1960s.
The shape might be the clincher. If you have Lesley Jackson's 20th Century Factory Glass you will see examples that are quite unlike Fiestaware, however, how large the range was, and how much was produced, is not known at present. From what you describe, this would appear to be 'Antique'. Turquoise is not uncommon, neither is Flemish (or Large Flemish). Antique Tinted in Amethyst is the least common colour.
* See Miller's 20th Century Glass, 2006