In his book Bvlgari Vincent Meylan indicates that the firm made a number of tiaras during the 1930s.

One jewel, which Vincent Meylan details, was a diamond sautoir, which could be disassembled to form a tiara and bracelets.

Another, which he details, was made in 1930. That tiara appears to have been in the Albion Art Collection at one time-- if this Pinterest site is correct. https://www.pinterest.com.au/pin/538602436661105700/

One of the issues hampering identification mentioned by Vincent Meylan is that not all the records from the 1930s have survived.

This link shows Gina Lollobrigida wearing a tiara which could also be worn as a necklace and bracelets.
See https://www.pinterest.com.au/pin/36028865741500448/?d=t&mt=login