A vintage square sterling silver pendant set with round cut colorless rhinestones, on a sterling silver Italian chain necklace. Made by Bysimon. 

Pendant - 3/4 x 1/2" - 2.4g - Marked "BY SIMON 925 ☆604 VI"

Chain - 16 inches long - 1.8g - Marked "925 ☆899 VI"

Check out the matching pair of earrings here: