Ammolite tag

"Where did you find such a thing?"

"In a cave overlooking our village.  At first I thought it was left by one of the children, it's a popular spot for, well, everyone.  But no one professed to know anything about it."

"Well then, where did it come from?"

"I don't know, the village shaman said it was from 'a time before time'"

"Typical. Those shamans, always got an answer for everything, especially when they have no damn clue themselves."

Ammolite is a rare material, gem quality specimens are found almost exclusively in Alberta, Canada.  It is an opalescent, organic material which coats the shells of ammonite fossils.