According to ancient belief, the stone absorbs negative energy directed against a person and transforms it into positive energy. The stone also protects the owner from committing bad deeds.
The tree of life in jewellery, apart from its wonderful aesthetic values, carries a strong symbolic context - the crown is our mind, the trunk - the body.
I think the silver works especially well against the black and is very striking. 
Chain length: approx. 50 cm