So you want to test gold or platinum with the help of your phone? The GemOro AuRACLE AGT2 Platinum/Gold Tester has you covered. It lets you use your iPad, iPhone, or iPod Touch in addition to a testing plate and a pen probe to start performing gold tests. The mobile app keeps track of your testing history. The device is portable and fits in your pocket. It shows its results via a bar graph or an analog meter readout.
The AGT2 is integrated with touch screen and mobile technology to test metals. Just bring your smart device, and you are set. Not cheap but quite an interesting app-enabled device.