Silver testing apparatus

A method of determining the content percentage of a precious metal within an unknown specimen containing said precious metal, comprising the steps of:

• providing a testing apparatus having an electrical circuit including a pen probe, said electrical circuit having a fixed resistance circuit path and a variable resistance circuit path;
• depositing an electrolyte from said pen probe onto said specimen to create a growing resistive layer between the pen probe and the specimen, said specimen and said growing resistive layer being in said variable resistance circuit path;
• determining the rate of growth of said resistive layer by measuring the flow of electrical current through said variable resistance circuit path and ascertaining a rate of change of the flow of electrical current through said variable resistance circuit path as said resistive layer grows, the rate of flow of electrical current through said resistive layer being proportionate to the rate of growth of said resistive layer;
• and
• comparing the rate of growth of said resistive layer to a rate of growth of a corresponding resistive layer on a calibration test sample;
• and
• deriving from said comparing step the concentration of said precious metal in said unknown specimen.

A testing apparatus for determining the content of precious metal within a specimen being tested, comprising:

• a meter including:
• a microprocessor having a memory;
• a source of electrical current connected to said microprocessor;
• an electrically conductive test pad;
• an indicator bar operably coupled to said microprocessor;
• an electronic circuit interconnecting said microprocessor, said indicator bar, said source of electrical current and said test pad;
• a pen probe connectable to said meter and said electronic circuit, said pen probe including:
• a non-conductive casing;
• a reservoir containing a supply of a corrosive electrolyte operable to create a resistive layer on said specimen when applied thereto due to corrosion of said precious metal in said specimen;
• said electronic circuit configured to establish two circuit paths for the flow of current with a fixed resistance circuit path and a variable resistance circuit path including said test pad, said object being tested when placed on said test pad, and said pen probe deposits said electrolyte on said specimen creating said resistive layer between said pen probe and said specimen, said microprocessor configured to identify a change in the rate of electrical current passing through said variable resistance circuit path as said resistive layer accumulates, the formation of said resistive layer being proportionate to the percentage of said precious metal in said specimen being tested.