This bangle isn't exactly a fake. However, the material used to make it is definitely under-alloyed, with an 880‰ AU content. The bangle is actually supposed to be made of 916 gold.
Abnormalities:
The clasp is noticeably small for the size of the chain.
There are 585 hallmarks on both sides of the clasp.
Material:
The surface material corresponds to the 585 stamp...