The main problem with artificial stones is that often they develop problems later on. For example, cubic zirconia will become cloudy and you need to be careful while cleaning it because it reacts badly with some agents. While moissanites can develop yellowish or greenish tinges. Also, jewelery with artificial stones doesn’t keep its value. A well cut diamond won’t lose its value after ten years whereas with a cubic zirconia (for example), the moment that the style of jewelery goes out of fashion it loses all value. People who buy diamonds buy them because it’s a good investment. Should you ever be in the depths of need then it would be possible to sell the diamond to feed the kids.

Moissanite has a hardness of 9.25 out of ten. The hardest gem is a diamond and sapphires are just below moissanite at 9 while cubic zirconia sits at an 8.5. Garnets have a hardness of between 6.5 and 7.5 and spinel is between 7.5 and 8. Anything lower than these would be too soft. Garnets are about the softest you can go while still maintaining durability.

While the garnet and spinel are still hard enough to endure as engagement stones (depending on what your gf does for a living), another red stone to consider is a ruby. It also depends on what shade of red she likes. Garnets tend to be darker than rubies, for example. For the green stones, either green cubic zirconia or green sapphires would be durable enough and both have sparkle. Although if your budget really is as tight as you say it is then I’d look at just getting cubic zirconia in the shades of red and green that you want. It’s probably the cheapest option and the easiest to come by.

It’s hard to help you find a place that custom makes jewelery because I have no idea where in the world you are. But if you look in your yellow pages for goldsmiths or gem wholesalers, you’re bound to find something. My only advice for this is go and see them knowing what you want. Even if you’ve just got a rough sketch on a napkin! That way the people at the shop know that they don’t have to try and sell you anything.

Another suggestion would be to ask your gf to look at various styles of rings and to find some three-stone (or however many stones you want) rings that she likes. It doesn’t matter if different stones are used, stones can be swapped out and if you see the goldsmith (i.e. jewelery maker) with a photo he’ll be able to give you the closest quote.

Good luck.

EDIT: As a side note, not all diamonds are blood diamonds. Google the Kimberly process and you’ll find out more about conflict-free diamonds. And the warlords who deal with blood diamonds deal with anything that they can sell, which includes other gemstones, gold and even their own grannies if they can get a price. It’s not just limited to diamonds.

I’m not sure what your actual budget is (under $3000 I guess from that massive question) but sapphires are real gemstones, so they do have an equivalent cost, but nothing near what a diamond would cost.

Having the ring custom-made could be costly, depending on what type of store you are looking at. A mall jewelry store will be more interested in up-selling you, than working with your budget and giving you the best you can afford. Find an independent jeweler, one that specializes in custom work. That or online store can really help you stay in your budget.

Places like http://www.overstock.com/ have a pretty great selection of gemstone jewelry, much of it with diamond accents, so I would start there to get an idea about pricing. Also check out http://www.bluenile.com/ which has a limited selection of gemstone jewelry, but good education documents so you can learn about what to look for and what factors in quality will affect the price. That way it will be easier to shop within a budget.

I have pink sapphire side stones with a center diamond (Canadian, not a blood diamond) in my engagement ring and I LOVE my ring. My husband had it custom made for me from his design.