welcome to HCM
As she is teething
tendency to chew on any object in their hand is common. She is attracted to it because of it colours as children love dark colours.so dont worry. its better to give some thing in her hand to chew on as she is teething and this will also prec=vent her from putting any bad harmful object into her mouth.
You give her a piece of brinjal ,cucumber ,carrot ( a big piece so that it wont get stuckked into throat).