These magnets are an excellent aid for detecting fallacious materials when precious metal testing. Additionally they are ideal for preliminary tests before the filing and acid testing processes.;Furthermore, owing to metallic inclusions, synthetic diamonds may be attracted or repelled by this magnet as natural diamonds are not magnetic.;Please do not include magnets in your order if you have also ordered the following items as magnets have an adverse effect on them and will cause damage;Movements;Circuits;Electrical equipment;Batteries