The most common and most likely answer to this crossword clue is the 9 letter word CRUCIBLES
I've seen this crossword clue in The Guardian
C
R
U
C
I
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Buddy explains!
The straight part
We know that "trials/trials" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case trials/trials = crucibles.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 CRUCIBLES mean?
CRUCIBLES noun- A cup-shaped piece of laboratory equipment used to contain chemical compounds when heating them to very high temperatures.
- A heat-resistant container in which metals are melted, usually at temperatures above 500°C, commonly made of graphite with clay as a binder.
- The bottom and hottest part of a blast furnace; the hearth.
- A very difficult and trying experience, that acts as a refining or hardening process.