Absolutely, that combination sounds so stylish.
If the outfit is black you could wear any colour shoes to make a statement without looking gaudy, it's a common choice,
However tortoiseshell is so versatile and unique you'll look elegant and eclectic no matter what colour you wear them with (just think of all the different colours of trench coats and macs with tortoiseshell buttons).
Brown might have been a little boring (and leopard print, a personal choice!), but with tortoiseshell you are elevated to a whole new level - and you won't even look as if you tried!