The most common and most likely answer to this crossword clue is the 8 letter word MINERALS
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More clues leading to the result MINERALS
Buddy explains!

The straight part
We know that "buried treasures" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case buried treasures = minerals.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 MINERALS mean?
MINERALS noun- Any naturally occurring inorganic material that has a (more or less) definite chemical composition and characteristic physical properties.
- Any inorganic material (as distinguished from animal or vegetable).
- (nutrition) Any inorganic element that is essential to nutrition; a dietary mineral.
- Mineral water.
- A soft drink, particularly a single serve bottle or can.
- A mine or mineral deposit.
- A poisonous or dangerous substance.