You need to be careful when choosing the center stone of the Engagement Ring. You need to consider their job, hobbies, and sports played.....how hard are they with their hands. Wearing an Emerald as an Engagement Ring you will need it insured because it is considered a brittle gemstone. Placing prongs and diamonds around the Emerald will help to ensure a better chance of wearing it without chipping the stone.
How to choose a Colored Gemstone? You must trust your eyes and pick what color you like. We all see color differently because of our cones and rods in our eyes. Emeralds are almost always included so you will usually see some sort of inclusion in it.
Remember no what to have the setting checked every 6 months to ensure you do not loose your Emerald.