All are lead free.  512, 514 and 516 are AP Non-toxic.  510 and 511 are CL label and may not be used in K-6 schools.  Read more about glaze safety.
Black Onyx loves texture and will exhibit a beautiful iridescence much like that of oil floating on water. The dark black color makes soft transitions to a deep cobalt blue where it breaks on texture. 
O  - OpaqueTP - Transparent
ST - Semi-transparentSO - Semi Opaque
Dinnerware Safe:1 - No lead or cadmium2 - No lead or cadmium released
Not Dinnerware Safe3 - Releases lead or cadmium4 - Not dinnerware safe due to texture
