This is a string that is knotted a card at 1 end. The card could be a swiping card or ID card (like some reporters often wear around the neck when they are on duty, they will be allowed to get in if they have the card for example).It is not a piece of jewellery. I am not sure if I can use the word "necklace".
necklace: a piece of jewellery consisting of a chain, string of beads, etc. worn around the neck
a diamond necklace
What is it called: a card necklace?