Gemstone multi-tester instrument with removable probe

A method for identifying precious stones and man-made stones using a handheld testing apparatus (100), the method comprising:

• using a probe (4) connected to the handheld testing apparatus;
• heating a metal tube (5a) using a heating element (24) of the handheld testing apparatus;
• sensing a temperature of the metal tube using a thermistor (25) of the handheld testing apparatus;
• placing the heated metal tube in contact with a stone (12, 13) under test;
• determining, using a microcontroller (36) of the handheld testing apparatus, an amount of heat transfer from the metal tube to the stone under test;
• generating at least one of a short wavelength ultra-violet (UV) light and a long wavelength UV light;
• illuminating the stone under test with at least one of the short wavelength UV light and the long wavelength UV light;
• detecting, using a photodiode of an optical detector (52), intensities of the short wavelength UV light and the long wavelength UV light reflected from the stone under test (12, 13) and generating a photocurrent;
• amplifying, using an amplifying circuit, the photocurrent and converting the amplified photocurrent into a proportional voltage signal;
• concurrently determining, using the microcontroller, the electrical properties and the optical properties of the stone under test during a single measurement session;
• identifying a type of the stone under test based on the determined at least one of:
• the electrical properties, the thermal properties, and the optical properties,
• receiving, using the microcontroller (36), the voltage signal and categorizing the voltage signal into at least one of three categories:
• (is) both the long wavelength UV light and the short wavelength UV light intensities are low, indicating moissanite, or (ii) both the long wavelength UV light and the short wavelength UV light intensities are high, indicating CVD/HPHT, or (iii) the long wavelength UV light intensity is high and the short wavelength UV light intensity is low, indicating diamond;
• and
• indicate the type of the stone under test by a visual indicator (6).

An apparatus for identifying precious stones and man-made stones, the apparatus comprising:

• a probe comprising a metal tube and a tip that makes contact with a flat surface of a stone under test,;
• a handheld device, electronically coupled with the probe, comprising:
• a thermal testing assembly coupled to the metal tube and configured to provide heat to the metal tube and sense a temperature of the metal tube;
• a high-voltage electrical conductivity testing assembly configured to apply a high-voltage signal to the stone under test and detect electrical conductivity of the stone under test;
• a microcontroller operably coupled to the thermal testing assembly and the high-voltage electrical conductivity testing assembly, and configured to perform a sequential gemstone testing process comprising:
• determine a thermal conductivity value of the stone under test;
• and
• perform a high-voltage electrical conductivity test only when the determined thermal conductivity value exceeds a predefined threshold value;
• and
• a visual indicator operably coupled to the microcontroller and configured to indicate the type of the stone under test.