link
Very rare and hard to get hold of.. sold out everywhere.
Its a replica of the locket (with moodstone) that the マーメイド wear in the TV 表示する H2o Just add Water and is an official licensed product.
The ネックレス is great quality. It is a highly polished stainless steel ネックレス that looks like silver. The locket opens and has three pictures of the マーメイド to put inside (or あなた can use your own photo).