Memberhelpme1122 : does it have to be a diamond? A 1ct moissanite would look lovely on her if you are both ok with it not really being a diamond. I know it really matters to some people but just remember that there are many many options. We chose a moissy because it was both eco and wallet friendly. I’ve had one coworker mention it’s a nice diamond and I told her it wasn’t a diamond but most people won’t even bring it up.
Memberhelpme1122 : Would you consider resale? You can get some lovely diamond rings at pawn shops and there is DiamondBistro https://diamondbistro.com/ and Loupe Troop https://loupetroop.com/. Also, check out Pricescope https://www.pricescope.com/ – there are diamond lovers on that site that can help you maximize your diamond dollar 
Good luck!
ETA – And to answer your question, I don’t think that a .5 ct on a size 4-5 will be too small, here is a pic of my friend’s .75ct D VVS2 on my size 6 finger:
MemberQuality also matters. I would much rather have a beautiful .5 carat than a cloudy 1 carat or bigger. That said, I think a half carat is on the smaller side from my perspective, but so what? The half carat rings bees have posted here are gorgeous.
MemberIf you want a full 1 carat diamond and don’t mind if it’s lab grown instead of naturally minded, you should start stalking the Lightbox website.
This one will be $1000 and you’ll get a full carat white diamond, plus a bonus tiny 1/8 carat pink or blue diamond. $1000 for a one carat diamond of this quality is unheard of anywhere else, even compared to other lab grown diamond, so I highly highly recommend snagging this when you see it become available again. You will need to get a ring setting and have a jeweler set it, but that’s not expensive. It’s about $50. And you can get settings as low as $200 or much more expensive depending on what you’re looking for.
Member.5 NOT AT ALL small. It is about Presence. Period. .44 center and .25 sides below. More dear than any solitaire I’ve had. F**k everyone’s version of “small”. Get what you love; what has Your Presence! Rise!
MemberDepends on where you live and the average size in that area and what her friends have.
MemberLike everyone is saying it depends on where you live, circle of friends, etc. In Europe it’s on the larger side of normal. In a big city in the US it is on the smaller side. But you can always make the stone look bigger with side stones, halo setting, etc. plus be proud you’re working within a budget. Estate jewelry, pre owned, lab created diamonds, etc can also be good options to get a diamind at a cheeper price. Mine is 0.5 center
Memberoh i think .5 ct on a size 4 is perfect, but that’s my taste, and I love round cuts, as i think they sparkle more.
You could ask her what she loves 🙂 then you’d be sure to get it right.
moissanite is a good option if she would prefer size over natural stone…but only she would know that!
best of luck!
MemberI have .50 round size 5 and I think it’s really nice. I went with a 1ct -3mm full eternity band to add a little weight to my set.
Member