Rock identification if possible please


I have polished to a certain extent but not cut, anyone know what it could be,
I haven’t found anything similar or been able to identify it %100 through searching online.

Chert? Where abouts did you find it?

JW :cowboy_hat_face:

It looks similar to Mutton Fat Jade, can you scratch it with a knife?

It either came out of the Temuka or opihi river I can’t quite remember, I ran a knife down it and it definitely left a mark.