The most common and most likely answer to this crossword clue is the 3 letter word ORE
I've seen this crossword clue in The Times
O
R
E
More clues leading to the result ORE
- Mineral aggregate originally rife in outskirts of Odense
- Mineral source almost disappeared from Pacific state
- Mineral course oddly abandoned
- Raw rock from Who revelatory
- Metal in half-finished state
- Valuable stuff making money for Scandinavians
- Money for old rope. Easy – at first
- Cruel person wasting good money
- Regularly sourced raw material
- Product of mine often found in foreign stores – for euros, moreover
Buddy explains!

The straight part
We know that "Mineral" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case mineral = ore.The cryptic/wordplay part
In cryptic crossword there's often an wordplay/cryptic part as well.This part involves a more complex hint, such as an anagram, homophone, hidden word, etc.
Sadly, We don't have an explanation for this specific crossword clue yet.
What does ORE mean?
ORE noun- Rock or other material that contains valuable or utilitarian materials; primarily a rock containing metals or gems for which it is typically mined and processed.