Estate Ring find- 2.5kt Sapphire 24kt gold- many many diamonds..

I came across this at a large Estate sale loaded with antiques. The "kids and grand kids" of the older lady that passed away didn't really know much about collectibles and valuables and antiques. I picked this up for about $300 and have had it awhile now. It belonged to a little old lady that passed away....the kids/grand kids needed money and sold everything at a great price just to get rid of it....(heartbreaking truly)
In any event, i took my chances and gave $300 not knowing what this really was but felt it was custom and genuine....it's VERY heavy too. It's a 1/2 sz too large for me so it just sits in the safe.
I took it to the largest Jeweler in our area and spoke to the owner who is a jeweler and he ran a few tests/used some gadgets etc and told me it's 24kt solid gold....all diamonds are the perfect S1 diamonds with the exception of two which have been replaced with a lesser perfect diamonds. The sapphire is 2.5kt and not man made....there's nothing written the the band, nothing at all....i forgot the total diamond weight/size but i was thrilled...he said i got a great amazing deal and it's worth a LOT more...lol...
He said it's a custom made piece and vintage/old but i forgot to ask how old....ugh.
Any ideas anyone?