These are remarkable beads!  They are a material called Shell Pearl, which is made with layers of Mother of Pearl.  This gives them the weight and texture of real pearls.  These have been dyed a beautiful pale Turquoise blue. 

Mounted on my historically accurate hoop findings or classic leverback findings. Also available as clip-on screw backs. 

These measure about 1" in length - the beads themselves are a small 10-12mm.  Please note these are natural beads so may have some minor variation in size and shape.