The most common and most likely answer to this crossword clue is the 5 letter word LOUPE
I've seen this crossword clue in Independent
L
O
U
P
E
Buddy explains!
The straight part
We know that "Thing used by jewellers to examine" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case thing used by jewellers to examine = loupe.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 LOUPE mean?
LOUPE noun- A magnifying glass, usually mounted in an eyepiece, often used by jewellers and watchmakers.
- A type of short-range binoculars used by surgeons and dentists.