There are many styles of engagement rings to choose from. Even if you do not find exactly what you are looking for in your local jeweler, you can choose to design the ring of your dreams. This will certainly be a fun and exciting adventure for you to experience.
If you and your significant other are dating seriously, then you have probably already brought up the idea of marriage. Most proposals are not completely a surprise because the couple talks about taking their relationship to the next step well before he picks out a ring. Since you have talked about getting married, you may as well talk about what kind of ring she will like to wear. There is nothing wrong with involving her in the process of designing the engagement ring. After all, she is going to be the one who wears it every single day.
You can always go the route of getting a little bit of her input and choosing the diamond engagement ring yourself. You just better hope she is not super picky about the design. If she has had a design idea in her head for a long time, she may not be willing to sacrifice that specific ring.