Just to note that onyx will probably be scratched and/or chipped by
steel shot. Usually onyx is polished using an acid of some sort. I
think you might find more on that in the Orchid postings
from earlier 2002.
Karen Bahr “the Rocklady” (@Rocklady)
May your gems always sparkle.
I think that this depends on which onyx is being discussed. The term
onyx is applied to banded calcite and also to Brazilian agate which
has been dyed black. The original onyx is a black, brown and white
banded agate. It is the banded calcite which is often polished by
acid-dipping and which is probably too soft to fare well when
tumbled with steel shot.