Diamond Selector II — Thermal Conductivity Meter Key benefits Quickly and reliably checks diamond authenticity by measuring thermal conductivity — saves time compared with slow or subjective visual tests. Clear visual and audible indications reduce user error: battery and ready lamps show instrument status; metal alert buzzer prevents false positives from metal contact. Portable, electronic design suitable for jewelers, pawn shops, gem buyers, and hobbyists who need fast onsite verification. Primary functions and performance Electronic thermal conductivity meter designed and manufactured to identify diamonds by their thermal conductivity. Provides lamp and sound indications to distinguish diamonds, simulants, and metal contact. Ready to use in about 30 seconds after powerup. How to prepare and operate 1. Insert the battery, aligning the mark on the battery as indicated. 2. Turn the Power Switch on. 3. Confirm the Battery Lamp lights up. 4. Wait about 30 seconds until the Ready Lamp lights up; the meter is then ready for testing. How to interpret results Diamond simulants (except synthetic diamonds): No sound. No red lamp boxes will light. Green and/or up to yellow lamp boxes may light depending on the type of simulant. Metal alert: Continuous buzzing sound indicates the Probe tip is touching metal. Metals have very thermal conductivity and can give the same indication as a diamond. The Diamond Selector II includes a Metal Alert buzzer to warn when the probe tip contacts metal. If you hear the Metal Alert buzzing, retouch the probe tip so it contacts only the tested stone. Operating environment and sample requirements Use environment: 5–35 degrees Celsius. Relative humidity: less than 80%. The gemstone to be tested must be clean, dry, and at room temperature. Materials and compatibility Designed for testing loose gemstones and mounted stones when the probe tip contacts only the stone surface (avoid touching metal settings). Compatible with natural diamonds and many simulants; note that synthetic stones may behave differently. Practical use scenarios Jewelry store: Quickly verify loose diamonds delivered from suppliers before display or . Pawn or appraisal: Screen incoming items at the counter to separate confirmed diamonds from simulants. Private buyers or gem hobbyists: Perform fast onsite checks when inspecting estate pieces or purchases to reduce risk. Notes for reliable results Ensure the probe tip touches only the gemstone surface; avoid contact with metal settings to prevent metal alert conditions and false readings. Allow the instrument to reach ready status (Ready Lamp) before testing. Test clean, dry, roomtemperature stones for accurate readings.