Unfortunately it’s allot of jealous people around, when you starting your Job or carrier, try not to be to fleshy. Then if you get to know people around you, you will see for them it’s tacky or not. But you don’t have to tell anybody it’s diamond, tell them , only if they ask, that this is CZ. If this is nice earrings, should be nothing tacky about them! Enjoy them. Good Luck!
I think it all depends on the type of corporation. If it’s an ad agency or modelling agency or similar co., everyone is arty-farty, yellow suspenders and all, so 2 earrings in each ear is par for the course. But in a more serious corpn, I can’t imagine, say, Carly Fiorina, or Marilyn vos Savant, or a partner in PricewaterhouseCoopers, with 2 diamonds in each ear! She’ll lose credibility.
So to answer your question, yeah, i’d think it was tacky.