This is a bangle or disc made from what I believe to be calcite. I am listing this and several other items that were part of the Chad Herrington collection. Most, if not all, the items from this collection were auctioned off a few years ago. Mr Herrington attributed these objects to roughly 1000-700 BCE to minority cultures in southeast Asia. This was possibly from the Ban Chiang culture. The stone appears chalky but solid and stable. It measures roughly 10 cm across the outside diameter and roughly 6.4 cm inside diameter. There are no signs of repair or restoration.