The most common and most likely answer to this crossword clue is the 6 letter word MINTED
I've seen this crossword clue in Financial Times
M
I
N
T
E
D
Buddy explains!
The straight part
We know that "rich" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case rich = minted.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 MINTED mean?
MINTED verb- To reproduce (coins), usually en masse, under licence.
- To invent; to forge; to fabricate; to fashion.
- (provincial) To try, attempt; take aim.
- (provincial) To try, attempt, endeavor; to take aim at; to try to hit; to purpose.
- To hint; suggest; insinuate.
- Made into coinage; coined
- Flavoured with mint
- Wealthy