Thanks everyone for your comments
Being a Murano novice I've always found the term 'Sommerso' a difficult one too
. I'd always thought of it as being kind of several layers of colour as opposed to just two (thinking here of those square sectioned Murano vases where the layers of colour are obviously visible).
Back to the bowl, there looks more than two layers. It's difficult to judge because of the way the colours reflect inside the glass. There is definitely a thin layer of turquoise on the inside, surrounded by a thicker pale yellow / straw colour. There is definitely straw on the outside and
I think another layer of turquoise somewhere inbetween
I think it does have a 'halo' - whether it's brighter than my own is for others to judge!
I know LSA has commissioned stuff in this turquoise colour. I bought a friend a couple of LSA kidney shaped dishes a couple of years ago for a present in this turquoise, just plain cased. I've seen examples of the bowl posted by Christine (I think this is in the other Sommerso thread now, created as I type) but this bowl doesn't show that obvious cased colour.