Hi - it looks like the Christian Dior logo lettering, similar to like what you see on the legendary Lady Christian Dior handbag that Princess Diana carried everywhere she went!
The signature on Christian Dior Jewelry (1947 - present) has several variations but most are dated.
Dior had an unbridled passion for Gardens and Roses, and in contrast to the logo lettering, much of Dior fashion and Jewelry still reflects this passion. Christian Dior continually reconstructed the magic of gardens. Design elements in both fashion and jewelry can be traced back to a fantastical Normandy-style Garden of Eden in Granville, France where he grew up.