Carnelian (Agate) Pendant and Pendant Head

This is a set of two items: a natural carnelian stone pendant and a separate pendant head.
They have been stored without being used. The pendant has a patterned design on both sides and the edges, as shown in the photos. The pendant measures 2.8cm in length and 1.5cm in width. The chain is 45cm long (screw-on type, no markings, some tarnishing).
The other pendant head measures 2.5cm in length and 2cm in width. Please note that these are home measurements, so slight errors may occur. Thank you for looking.