Just to play devil's advocate -- why not spend a bit of money on a small diamond, or perhaps even a semi-precious stone? When people buy CZ engagement rings, they don't usually go for a modest look. Most CZ rings are rather -- aspirational?
I would never dream of buying a CZ engagement ring, personally. I think most people tend to assume that engagement rings, unlike perhaps diamond ear studs, are the real thing. I'm not that interested in representing myself, via jewelry, as something that I'm not.
Of course, others are more light-hearted about jewelry. To them, it's all really just for fun and they don't care if their 4 carat engagement ring is fake or real. And kudos to them -- it's just a personal preference. But I don't really buy the "finances" argument when it comes to engagement rings in particular -- other items of jewelry, maybe. I think in the engagement-ring instance it really is not unlike the woman who carries a fake Chanel bag.
i used to buy into the whole "diamonds are a girl's best friend" thing. i obsessed over having the perfect diamond, in the perfect setting. that is, until finances came into play. we had a choice to spend money on a real diamond, or get the same thing in a simulant and use the leftover cash for a downpayment on our home. our choice to invest in building a home for our family seemed to make more sense, so practicality won and the choice was simple.
i LOVE how diamonds look. i LOVE how they sparkle. but i HATE the cost associated with having one, both financially and ethically. a sim allows me to satisfy my desire for something beautiful, but not sacrifice the priorities in my life. owning a diamond, simply isn't one of them.
to my friends and family, i have been forthcoming with our decision to forego on a diamond, but i simply do not see the necessity in having to explain myself to EVERYONE. if someone was to question my ring's authenticity, i will tell the truth. "Yes, this is an authentic moissanite". if people are going to assume that i'm wearing a diamond, then so be it. but, i'm not about to wear a sign on my forehead saying "hey stranger, just so you know, this is not a real diamond and i do not wish to misrepresent myself with my jewelry, hope you understand"
people can make all the assumptions they want, but truth be told, i don't aspire to owning a real diamond. just like i don't aspire to own a real designer hand bag, i don't have the money for it and in my financial situation, owning an authentic handbag would be pretty stupid.... but if i passed by a cart downtown that sold a "lookalike" handbag that complimented my outfit, damn skippy i'm buying it.
as far as i'm concerned, there's no justification needed, because i know that real or not, the symbolism behind the ring is what matters.