I just had another newly engaged couple in yesterday. He had picked out a band from me and she was thrilled with it. It was a completely nontraditional engagement ring as it didn't even have a center stone. In the picture to the left it's the bottom ring. But the young gentleman seemed to have a very good grasp of what his intended would like from the moment he walked in. Remember that it is the intent behind the ring that makes it what it is, not the actual piece.
So now you (the proposer) has figured out what kind of style your intended would like (well hopefully) and you have to deal with another issue. What kind of stone are you going to put in the ring? Diamonds, obviously, are the traditional choice but they are not the only option. Durability, however, is an issue that must be raised immediately. This is a ring that is going to be worn every day for a very long time and consequently it would be nice if it would hold up well. For this reason I usually recommend either diamonds, rubies or sapphires because these are the most durable of gem materials. Now mind you any stone can be broken (diamonds included---their hardness refers to scratch hardness not breakage) and, over time, most will show signs of wear and tear but usually these three will hold up better than most others. Stones like opals, tanzanite, pearls, etc. are extremely fragile and are definitely not good choices. Emeralds also tend to break fairly easily (although their scratch hardness isn't so bad) and are not a good choice.
The good news is that sapphires do come in a wide range of colors so the palette of colors available to you is fairly broad. For those of you concerned about the sourcing of diamonds (more on that in a future post) sapphires offer an excellent option. Personally I think they are far more interesting, but I think there is such a strong feeling about getting a diamond by many women that it shouldn't be ignored. My wife, who has a 10 ct. tourmaline in her engagement ring and numerous sapphire rings, still wanted a diamond for her 20th anniversary present and I was happy to oblige.
The question of diamond vs. sapphire however is something that should definitely be felt out beforehand. While I don't know many women who would refuse a diamond, some people, for a variety of reasons, just don't want one. On the other hand I routinely get women in who say that they don't want a diamond, until they actually start trying on rings. Maybe it's just my ideal cut Lazare Diamonds that sparkle so much that changes their minds or maybe it's just that tradition thing kicking in again. Or perhaps they realize that diamonds just can go with anything else they put on.