Can I replace the magnetic scale with a test using a simple magnet?

Yes and no. In theory, a magnet can be used to determine whether an object exhibits diamagnetism or paramagnetism. However, the magnetic forces produced by conventional magnets are often so weak that they cannot be detected by the human eye. To take a measurement, you would therefore need a very strong magnet. For this reason, a magnetic balance capable of measuring down to the hundredths of a gram is recommended. This allows you to detect even very subtle differences and obtain clear results.