We all know that Rihanna, the Barbados-born beauty, is not afraid to push fashion boundaries, so we take special note of what the songstress wears.

Our rating for the sculptural statement necklace made of silver plated brass and black iguana leather that Rihanna is seen wearing here -- it retails for $780 -- is XXX, as in excellent.

The piece is by Maria Francesca Pepe, an Italian designer whose UK-based label, MariaFrancescaPepe, is known for dramatic pieces, which are often seen draped around the necks of runway models at London Fashion Week.

A spokesperson for Pepe, who makes equally sculptural clothes, told StyleList that Rihanna owns many MariaFrancescaPepe items and loves the line.

The sexy singer -- who posed half naked with a live cougar for "Rated R" -- clasped onto this tubular piece, a half-circle on a heavy chain link, at a recent photo shoot for the album in Sydney, Australia. Rihanna was also photographed rocking out another chain by the designer at a party in London last year.

Unfortunately, this particular necklace is not currently in stores, but you can check out similar styles on the designer's Web site.

For style scoop from another daring performer, check out Pink's recent chat with Oprah, where the singer discusses her high-flying Grammys fashion.