How would you interpret the phrase "cast in stone"? It would be anomalous for someone to pour magma into a mold.
The ordinary view would be that "cast" refers generally to the making or composition of anything by any means. Compare a few senses from Merriam-Webster:
[v.t.] 3(a) to dispose or arrange into parts or into a suitable form or order - I shall cast what I have to say under two principal heads.
[n.] 2(a) the form in which a thing is constructed
[n.] 10(a) shape; appearance - the delicate cast of her features
The ordinary view would be that "cast" refers generally to the making or composition of anything by any means. Compare a few senses from Merriam-Webster:
[v.t.] 3(a) to dispose or arrange into parts or into a suitable form or order - I shall cast what I have to say under two principal heads.
[n.] 2(a) the form in which a thing is constructed
[n.] 10(a) shape; appearance - the delicate cast of her features
https://www.merriam-webster.com/dictionary/cast