Here is something you don't see every day - an Ouroboros snake ... crescent. 
 
This crescent is modelled with old cut diamonds and rose cuts for the smallest stones, set in silver, in open backed settings, with a gold backed framework, the snake's ruby eye set in gold.
 
The ouroboros, or the serpent which bites or swallows its own tail, is a well known symbol in esoteric doctrines. It is a symbol for death and rebirth, renewal of life, and also a symbol for the cosmos or endless cycles in the universe.
 
The moon can also be seen as a metaphor for the ebb and flow of life.
Its ability to change phases and transition back and forth between a dark new moon and a bright full moon, reflects life itself, encompassing birth, growth, death and rebirth.
 
The crescent
As the lunar cycle nears its completion, less than half of the moon’s surface is visible, and it appears in the sky as a letter ‘C’, and gradually receding. With the sacred cycle near its end, this is a time to rest and recuperate, and focus on self-care and recharging the batteries. It is also a period of surrender; letting go of things that no longer serve us, and readying yourself for the moon’s new cycle.
 
measures - 46mm x 37mm
weighs - 8.9g
condition - excellent (converted from a brooch)
English circa 1890