The most common and most likely answer to this crossword clue is the 10 letter word MINERALOGY
I've seen this crossword clue in The Times
M
I
N
E
R
A
L
O
G
Y
More clues leading to the result MINERALOGY
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The straight part
We know that "Study" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case study = mineralogy.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 MINERALOGY mean?
MINERALOGY noun- The branch of petrology that studies minerals.
- Its mineral materials.
- A treatise on mineralogy.