I would just try it for about 10 sec if it is going to spark you will know and can shut it off.
How many of us have accidently put a fork or spoon or foil in the microwave and caught it after the first few sparks and pops? It did not blow up your microwave then.
The fabric is "paint" with gold it does not have real "gold" on it. I would bet your fabric will work just fine and be beautiful gifts.
CAT