The most common and most likely answer to this crossword clue is the 7 letter word BORACIC
I've seen this crossword clue in The Guardian
B
O
R
A
C
I
C
More clues leading to the result BORACIC
- Skint revolutionary about to knock off, I see
- Gold, auric edges in pen containing a metalloid
- Penniless bachelor caught in Cairo, embarrassed
- Rocking old cradle for starters, a crib broke
- Penniless in London and Cairo away in the distant past
- Penniless actor, losing heart, retrained in burlesque in Canada first of all
- Penniless tobacco picker could sew up pocket with this
- ‘Penniless’ writer conceals gold account
- Turning to steal from account, one gets caught, becomes penniless
- Broke wind by military bigwig
Buddy explains!

The straight part
We know that "containing a metalloid" is the straight/definition part of the clue. The straight part is often a synonym or definition, in this case containing a metalloid = boracic.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 BORACIC mean?
BORACIC adjective- Relating to, or impregnated with borax.
- Of, pertaining to, or containing the element boron.
- Penniless