Magatama Idol Kaguya explains:Edit
"This is a Black Bear Magatama. Even though it's a Magatama is soft and fluffy like fur! When it's winter I think a strong winter coat will start to grow over it, so we should guard it closely during that time. Like the Black Bear it is named after after there are some white spots in the fur. Come to think of it, Kintoki-san said she wants to eat Bear-Nabe so maybe she'll make it for us too?! After making this strong the fur has turned kind of gold in colour. I don't even know if this is a Magatama anymore."