I am a prominent LW poster; this is a through-away account because my girlfriend also uses LW.

I would like to propose to my girlfriend in the near future. For this I would like to use a diamond ring. I have never bought one before, so would appreciate any advice. The main things I would like help with:

• Not paying extra due to ignorance
• Ensuring she never has cause to regret the choice of stone/ring.
• Anything else you think I should know.

Some background in case it helps:

• I live in NYC, so have access to the diamond district.
• I am leaning towards an artificial diamond, as it seems hard to guarantee conflict-free otherwise (which does not seem romantic!) and we are both pretty pro-science.
• My price range is orgjrra bar naq gra gubhfnaq qbyynef, ohg V jbhyq cersre gbjneqf gur ybjre raq bs gur enatr
• My girlfreind is neither unusually fat nor unusually skinny for an American of marriageable age. She is white.
• She does not wear much jewelry. The stuff she has is mainly (fake?) yellow gold and silver, mainly gifts.
• I am probably looking for a relatively simple design, round stone.