These pieces of naturally rough/raw tiger's eye came from the National Geographic collection. 
Every so often we need to purchase a new rock Tumbler. Each time we purchase a new rock Tumbler, the company we buy from sends us rocks. We try to focus on tumbling Scottish rocks but once in a while we do tumble up one of the international ones. 
Tiger's eye is a little less tough than the agates and quartz crystals from Scotland which we polish. If we wanted to tumble up the tigers eye we would have to do it in a barrel with softer material. This means that they were sat on the side waiting to be tumbled for the last two or three years. 
These pieces of Tiger's eye spoke to Katriona in a dream one night and told her that they wanted to be sold.
So you can know by rough unpolished tigers eye through the stone circle at least until we run out. Personally we think it looks better rough.