I think that this brooch dates to the 1960s.
Great architectural design, various layers of blocks, which are either shiny, finely textured, or roughly textured.
Pin on reverse which has a roll-over safety catch.
No maker's mark but has the numbers 1347 on the reverse side.
The brooch measures approx. 5.3cm from top to bottom (longest measurement), and is approx 4.8 cm at widest point.
Condition is vintage good - some wear to goldtone, but this is not really noticeable, and there is the odd ding.