For the USA, an unworn 5 cent nickel weighs 5 grams. When I was testing one of those tiny portable scales that are battery operated, I would use 1, 2, and 3 nickels to determine if it was close to being accurate.
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I was considering picking up some accurate weights for calibrating the scale properly, but if nickels will work, I could probably figure out how to procure some nickels instead. Right now, I have a roll of quarters and zero nickels in the house. I was using one to open up my electric candles, but it went missing, so I'm using a dime instead.