raw ore; unrefined ore
Refers to ore as mined, before smelting or processing. Used in mining and industrial contexts.
この鉱山では良質の原石が採れる。
High-quality raw ore is mined at this mine.
rough gemstone; uncut gem
A gemstone in its natural state, before cutting and polishing. Also used metaphorically for a person with raw talent.
彼はまだ原石だが、磨けば光るだろう。
He's still a rough diamond, but with polishing he'll shine.
この原石をカットして指輪にします。
We'll cut this rough gemstone and make it into a ring.