High quality diamonds look grayer/silvery under bright light, whereas CZ produces rainbows. I own both, and it's easy to tell the difference if you're, say, out

High quality diamonds look grayer/silvery under bright light, whereas CZ produces rainbows. I own both, and it's easy to tell the difference if you're, say, outdoors in the summer, or under full-spectrum lighting. Moissanite is closer, but moissanite still has more of a "rainbow" look, and is often yellowish. If a friend of mine was showing off her engagement ring and it was refracting a little rainbow on her finger in the sun (like this http://upload.wikimedia.org/wikipedia/commons/b/bd/CZ_brilliant.jpg http://upload.wikimedia.org/wikipedia/commons/b/bd/CZ_brilli...) I obviously wouldn't say anything, but come on. Getting a CZ engagement ring is going to lead to an awkward situation at some point.