Ok, here is a new one on me. I have never seen this pattern before. It is made by JAJ Pyrex in England and has white shamrocks/clover leaf pattern. It is part of a chip and dip set that would have included a smaller white opal bowl with green clover leaf pattern.
The bowl is in pretty good condition, with some wear to the surface in the way of small scratches in the finish and light wear to the inside.
Will be available soon in my booth at the Almonte Antique Market, 26 Mill Street, Almonte ON.
Priced at $40
Please note: This item is now SOLD!!
fabfindsblog 
Hello, lovely bowls! I happened upon your page when researching a little one I picked up the other day and it just so happens to be your missing white with green shamrocks from this set! Would love to know any further info you may have on this pattern….
Hi. I do love this pattern. I wish I knew more about it, like the year it was made and what sizes it was available in. So far, I don’t know but I am doing more research and if I find anything out, I will post it here. Thanks for checking out my blog.