The most common and most likely answer to this crossword clue is the 7 letter word PYRITES
I've seen this crossword clue in Independent
P
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More clues leading to the result PYRITES
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 = pyrites.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 PYRITES mean?
PYRITES noun- The common mineral iron disulfide (FeS2), of a pale brass-yellow color and brilliant metallic luster, crystallizing in the isometric system.
- (usually as a plural: pyrites) Any metallic-looking sulphide, such as the above, which is the most common.
- (usually as a plural: pyrites) Any metal dichalcogenide that is isostructural to the common mineral.