Hi Anne, welcome to the Board.
The easy part ... don't be concerned about the mention of "fake Ysart weights" - they do not apply (as far as I know) to weights with a sulphide.
Now the trcky bit ...Yes it's an Ysart weight, but which Ysart?
There are many examples of the exact same sulphide in other weights that have "Ysart canes" in them. Many people claim Paul Ysart as the maker and others claim Salvador Ysart (Paul's father) made them.
I believe that the majority I have seen, if not all, were made by Salvador Ysart and probably in the years 1946 to around 1953 at the Ysart Brothers works (tradename "Vasart").
But there is one I have seen online that was faceted to the top and sides and the base flat polished - and those features could indicate Paul rather than Salvador - but could the faceting have been done as repair work> Hmm!!!It wiould take a lot of typing to explain why I believe what I do, but this subject has been discussed within another thread
from March 2018 - Sulphide Paperweight info neededPlease take some time to browse that thread at leisure. It is quite complex, especially for folk new to the subject. But I have set out many pros and cons as to why I favour Salvador Ysart as the maker.
A lot of my research into these (and other) Ysart weights has been through analysis of the millefiori canes. I have produced, from weights in my own collection, a Gallery of 416 "Early Ysart Canes" published over three issues of the Paperweight Collectors Circle Newsletter (2016 / 2017. Nos 122, 123, 124).
The analysis has shown (from 80 "Salvador items" and about 80 "Paul Ysart items with millefiori") 14 matched canes used by both Salvador and Paul. But only one of the two canes in your weiight appears within my collection - the "orange one" - and I have that noted as "Early Ysart / Salvador".
Notes:
a) The match of cane that John mentioned for both your weight and his "striped ground weight" is not a true full match - the main colour of the internal elements differ (on my screen). His cane has white for the detailed elements but yours is a clear pastel blue for the internal elements. However it is the same structure (13 internal elements around 6 inner elements around a single cane centre. But ...
b) John's cane DOES appear in my Gallery (for those readers with copies of the Newsletters, it is No 337 in Issue 124, July 2017). And that cane IS matched for use in at least one of my Paul Ysart weights. But the rest of the features of John's weight point to Salvador as the maker.
c) In your sulphide weight, the other cane (Orange main colouring) appears in my Cane Gallery as No 322, in Issue 124, July 2017. I have not found it in any of my Paul Ysart weights, so I have it marked as "Early Ysart / Salvador".
In summary, takiing account of my remarks here and in the thread that John linked to, I believe your weight was made by Salvador Ysart.
I look forward to other folks' comments.