This is a pendant made with a green stripe (most likely dyed) agate cabochon.  With the bail, it is approximately 59mm / 2.3 inches long.  
 
Agate is an excellent stone for rebalancing and harmonizing body, mind and spirit.  It cleanses and stabilises the aura, eliminating and transforming negativity.  Agate enhances mental function, improving concentration, perception and analytical abilities. Wearing Druzy gemstones is believed to promote relaxation and stress relief.  People use it to connect more easily with their own inherent healing powers.
 
The pendant will arrive in a small gift bag with an 18” waxed cord necklace.