Cool and calming...
A soothing, translucent grey-blue chalcedony is set is 18k yellow gold and a brushed sterling silver crescent swings from a hidden hinge below, accented with a sparkling diamond.

Chalcedony (17.5mm x 12.5mm)
.10 TCT lab grown diamonds (F, VS)
18k gold & sterling silver 

Approximately 1” long