Mastering The Diamond Selector II: The Definitive Professional Guide To Accurate Gemstone Testing
Successfully operating the Diamond Selector II requires precise calibration of the thermal conductivity probe relative to the ambient temperature and the carat weight of the gemstone. To achieve a valid reading, the device must be calibrated so the level meter rests at the specific starting point indicated by the manufacturer's scale, ensuring that the transition from green to red lights accurately reflects a diamond’s unique thermal transfer rate of over 1000 W/mK.
Pre-Operation Protocols and Calibration Requirements
Before initiating a test with the Diamond Selector II, understanding the physical principles of the device is essential. This tool functions as a thermal conductivity meter. Because diamonds are among the most efficient heat conductors on Earth, the device sends a small amount of heat through its copper-tipped probe and measures how quickly that heat dissipates into the stone. However, factors such as the size of the stone and the temperature of the room significantly alter these readings. A small diamond in a cold room will dissipate heat differently than a large diamond in a humid, warm environment.
To ensure the integrity of your results, you must adhere to a strict preparation checklist. Failure to clean the gemstone or stabilize the device's internal circuitry will lead to false positives or inconclusive "dead zones" on the level meter.
Essential Gear and Environmental Standards
- Power Source: A fresh 9V alkaline battery is mandatory. Avoid zinc-carbon batteries as they lack the consistent voltage discharge required for the heating element.
- Gemstone Cleaning Kit: Isopropyl alcohol (90%+) and a lint-free microfiber cloth to remove skin oils, which can insulate the stone and cause false negatives.
- Ambient Temperature: The testing environment should ideally be between 10°C and 30°C (50°F - 86°F). Extreme temperatures render the internal calibration table inaccurate.
- Stabilization Period: Allow the device to sit in the testing room for at least 10 minutes to reach thermal equilibrium before powering it on.
- Mounting Equipment: Use a metal testing tray for loose stones. The tray acts as a secondary ground, though the user must ensure the probe does not touch the metal itself during the actual test.
Technical Execution: Operating the Diamond Selector II
The accuracy of the Diamond Selector II is almost entirely dependent on the "Volume" or "Level" adjustment performed before the probe touches the stone. This is not a "one-size-fits-all" tool; you must adjust the sensitivity every time you switch between stones of significantly different sizes or when the room temperature shifts.
Step 1: Power Initialization and Thermal Warm-up
Turn the "Volume" dial clockwise until the device clicks on. The "Power" lamp (usually green) will illuminate. Do not attempt to test a stone immediately. The thermal probe contains a heating element that requires roughly 30 seconds to reach a stable operating temperature. Wait for the "Ready" or "Lamp on" indicator (typically a second light) to glow before proceeding to calibration.
Step 2: Atmospheric and Mass Calibration
Consult the calibration chart located on the back of the device or in the manual. This chart cross-references the current air temperature with the estimated carat weight of the stone. Locate the corresponding number (typically 1 through 7) on the chart. Rotate the "Volume" dial until the level meter lights up to the exact number required.
Pro-Tip: If you do not know the exact carat weight, estimate conservatively. For stones under 0.05ct, a higher sensitivity setting (Level 6 or 7) is usually required. For stones over 0.50ct, a lower setting (Level 3 or 4) prevents over-sensitivity.
Step 3: Handling and Positioning the Stone
If the stone is loose, place it in the indentation of the metal testing tray. If the stone is mounted in jewelry, hold the jewelry piece firmly. You must ensure the stone is dry and at room temperature. Do not test a stone that has just been worn against skin or held under a hot jeweler's lamp, as the residual heat will skew the thermal conductivity reading.
Step 4: Vertical Probe Application
Remove the protective plastic cap from the probe. Hold the Diamond Selector II at a 90-degree angle relative to the facet of the stone (usually the table or the largest pavilion facet). Apply gentle but firm pressure. The probe tip is spring-loaded; ensure it retracts slightly to guarantee full surface contact.
Warning: Never apply the probe at an angle. Doing so reduces the contact surface area, which leads to insufficient heat transfer and an incorrect "negative" reading for a genuine diamond.
Step 5: Interpreting the Visual and Auditory Feedback
Observe the level meter and listen for the internal buzzer. A genuine diamond will cause the lights to rapidly climb into the red zone (levels 9 and 10) and trigger a continuous high-pitched beep.
- Green/Yellow Lights Only: The stone is likely Cubic Zirconia (CZ), glass, or synthetic sapphire.
- Rapid Beeping with Red Lights: The stone is a diamond (or moissanite).
- Erratic Chirping/Metal Alert: If the probe slips off the stone and touches the metal setting (the ring prongs or the testing tray), the device will emit a distinct, rapid "chirping" sound. This is the metal-contact warning, not a diamond confirmation.
Diamond Selector II - TEZ RAFTAR
Comparative Calibration and Sensitivity Metrics
The following table provides the standard calibration levels for the Diamond Selector II based on the industry-standard JDT (Japanese Diamond Tester) metrics. These values are calibrated for a standard 9V output and assume a clean probe tip.
| Ambient Temperature | Small Stones (under 0.05ct) | Medium Stones (0.06ct - 0.50ct) | Large Stones (0.51ct - 2.0ct+) |
|---|---|---|---|
| Cold (10°C / 50°F) | Level 6 | Level 4 | Level 2 |
| Moderate (20°C / 68°F) | Level 5 | Level 3 | Level 1 |
| Warm (30°C / 86°F) | Level 4 | Level 2 | Level 1 |
| Hot (35°C+ / 95°F+) | Level 3 | Level 1 | Level 0 |
Common Operational Failures and Technical Remedies
Even with a high-quality Diamond Selector II, users often encounter anomalies that suggest the device is malfunctioning. Most of these issues stem from environmental variables or improper maintenance of the thermal tip.
Scenario: The device indicates "Diamond" for every surface, including air.
- Root Cause: The sensitivity (Volume) is set too high for the current room temperature, or the battery is extremely low, causing the internal reference voltage to drop.
- Actionable Fix: Turn the volume dial back until only the first one or two green lights are visible. Replace the 9V battery with a high-performance lithium or alkaline variant.
Scenario: A known diamond fails to trigger the red lights or the beep.
- Root Cause: The probe tip is oxidized or coated in oil, or the stone is too cold. Thermal transfer is being blocked by a microscopic barrier.
- Actionable Fix: Gently wipe the probe tip with a piece of clean paper or a specialized probe cleaning stick. Ensure the stone has been cleaned with alcohol and allowed to sit at room temperature for five minutes.
Scenario: The device produces a constant "Metal Alert" even when not touching metal.
- Root Cause: High humidity or moisture on the surface of the stone or the user’s hands is creating a conductive bridge to the metal casing of the probe.
- Actionable Fix: Use a dehumidifier in the testing area. Dry the stone thoroughly with a hairdryer on a "cool" setting and wear latex/nitrile gloves to isolate your hand's moisture from the testing process.
Scenario: The "Ready" lamp never turns on.
- Root Cause: The internal heating element is burnt out or the battery connection is loose.
- Actionable Fix: Check the battery terminals for corrosion and ensure a tight fit. If the light remains off after 2 minutes of warm-up with a new battery, the internal filament has likely failed, requiring device replacement.
Frequently Asked Questions
Can the Diamond Selector II distinguish between Diamond and Moissanite?
No, the Diamond Selector II cannot distinguish between the two because moissanite is also thermally conductive. To differentiate them, you must use a "Moissanite Tester" which measures electrical conductivity rather than thermal conductivity.
Why does the device beep rapidly when I touch the metal setting?
This is a built-in safety feature called the Metal Alert. It notifies the user that the probe is touching the jewelry mounting (gold, platinum, or silver) rather than the stone, preventing a false positive reading caused by the metal's high conductivity.
How often should I clean the probe tip?
The probe tip should be cleaned after every 20 tests or whenever you notice the "Ready" lamp taking longer than usual to illuminate. Use a simple piece of white bond paper to gently wipe the tip, as the slight abrasiveness of the paper removes carbon buildup without damaging the copper.
Does this device work on synthetic/lab-grown diamonds?
Yes. Lab-grown diamonds have the exact same chemical composition and thermal conductivity as natural diamonds. The Diamond Selector II will identify a lab-grown diamond as a "Diamond," but it cannot tell you if the stone is natural or earth-mined.
What should I do if the level meter fluctuates wildly?
Wild fluctuations usually indicate electromagnetic interference (EMI) from nearby electronics like cell phones or fluorescent lights. Move the testing station away from electronic devices and ensure you are not standing directly under a high-voltage light fixture.
Professional Gemological Assessment
Mastering the Diamond Selector II is a foundational skill for anyone handling precious stones, providing a reliable first line of defense against common simulants. For absolute certainty in high-value transactions, always supplement thermal testing with visual inspections under 10x magnification.
