This bendy necklace appears to be 5 mm in diameter, not 6 mm. Also, it is dark and dull, not shiny like the photo. It does not reflect light. It is not very pretty.  Maybe with the metal polish it would come to life, but I did not purchase it to have more house work. It does appear to be durable. Update: I did try metal polish and the results were even worse. I ended up throwing this out. It looks nothing like the photo - looks like something you would find in a garage floor.  Went into the trash. Hi Amazon - would you please monitor your 3rd party sellers better?  Too many risky buys, false adverting, poor customer service from the third party sellers.