Lots of jewelry shops offer “Tiffany-style” rings or “Cartier-style” rings.
The thing about this is that:
a. They are NOT Tiffany & Co or Cartier rings if they are being sold by another jewelry store
b. You won’t be fooling anyone with a “styled” ring
c. trademark and patent laws ensure that no other jewelry stores will be able to see a ring that looks “that much” like a Tiffany & Co/Cartier ring
d. Brands such as Tiffany, Cartier, Louis Vuitton and the like have been cracking down on counterfeiters and have been prosecuting
That doesn’t matter, you still want a ring that LOOKS like Tiffany & Co. or Cartier even if it isn’t.