Diamond detecting apparatus and method

Apparatus for testing a stone for genuineness as a diamond with a single probe applied to the stone surface, the apparatus comprising:

• a) a thermally and electrically conductive probe tip mounted in a housing;
• b) a thermal conductivity measuring assembly mounted in the housing and connected to the probe tip;
• c) an electrical conductivity measuring assembly mounted in the housing and connected to the probe tip for applying a high direct current voltage through the stone and measuring the direct current flowing therethrough;
• d) thermal conductivity display means mounted in the housing and connected to the thermal conductivity measuring assembly for displaying an indication of the thermal conductivity of the stone relative to the thermal conductivity of diamond;
• e) electrical conductivity display means mounted in the housing and connected to the electrical conductivity measuring assembly for displaying an indication of the electrical conductivity of the stone relative to the electrical conductivity of diamond;
• f) an external electrical contact on the housing surface connected to the electrical conductivity measuring assembly for completing an electrical circuit through the user when the user holds an electrically conductive item on which the stone is mounted and also holds the housing, while contacting the electrical contact;
• g) circuitry means in the housing connected to the two assemblies for sequentially actuating first one of the assemblies and then the other of the assemblies;
• h) the thermal and electrical conductivity display means including visible and audible displays;
• and
• i) in which the thermal conductivity measuring assembly is actuated first, and then the electrical conductivity measuring assembly is actuated to thereby indicate first if the stone has the thermal conductivity consistent with diamond and then if the stone has the electrical conductivity consistent with diamond.

A method of distinguishing between a true diamond and another stone when the stone is mounted on an electrically conductive mounting using two hands of a user the method comprising:

• a) providing a housing with a thermally and electrically conductive probe tip having both thermal and electrical conductivity measuring assemblies connected thereto, an external electrical contact connected to the electrical conductivity measuring assembly, and display means for indicating when the stone has the thermal and electrical conductivity consistent with diamond;
• b) holding the stone mounting in one hand;
• c) holding the housing in the other hand while contacting the external contact;
• d) applying the probe tip to the surface of the stone;
• e) causing the thermal conductivity measuring assembly to be actuated to thereby indicate by the display means what the thermal conductivity of the stone is relative to diamond;
• and
• f) causing the electrical conductivity measuring assembly to be actuated to indicate by the display means what the electrical conductivity is relative to diamond.