This is a bracelet, and it's jewelry worn around the arm, but what about jewelry worn around the legs? What do you call it? Is there a particular name for it, or do you just have to call it leg-jewelry?
Word Request – What Do You Call Bracelets Worn Around the Legs?
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Related Solutions
I believe you're talking about the trunk (American English). The back part where you put stuff in such as luggage. 
Just a quick tip for next time, if you go on Google and select "images" and then write "Car parts names in English" you will see a bunch of car parts with names from ESL websites.
This is just called a nose chain. See its Wikipedia page:
Simply put, the nose chain is a link between a nose piercing and an ear piercing. Typically, these "chains" are just that: chain links, usually (though not always) made of some kind of metal. Yet, besides actual chains, the term "nose chain" can denote other types of connecting materials between nose and ear piercings, such as the common alternative of rosary beads. Other connectors can be used as well.
Best Answer
There are "anklets", which are worn around the ankles.
From Wikipedia:
Note that "ankle bracelet" in some contexts could be misconstrued as an ankle monitoring device used in law enforcement.
Also, please note that "bracelets" are worn around the wrists. It is clear and natural to say someone wore a bracelet on their arm, but most native speakers will take that to mean it is on that person's wrist. I think the object in your picture would be worn on the upper arm, and therefore is not a bracelet.
There is something called a "bangle". Here is Wikipedia on bangles, for convenience:
"Bangle" on Wikipedia
But yes, in some cases you would simply say "jewelry". (I suggest not calling it a "jewel") Leg-jewelry is little bit odd, so, personally, I would rearrange the phrase to say (He wore) "jewelry on his leg".