Introduction
The GemOro Pro-D 3 Diamond Tester is a precision tool designed for the identification, detection, and separation of diamonds from other materials such as cubic zirconia, moissanite, and white sapphire. This enhanced testing technology evaluates stones using cutting-edge scanning techniques and advanced software analysis, ensuring highly accurate test results. It features LED stone illumination and UV fluorescence detection, aiding in the observation of subtle nuances and potential diamond treatments. The device offers versatile power options, including Micro USB, rechargeable NiMH batteries, or AAA Alkaline batteries, with a battery-saving auto-off function.

What's Included
Your GemOro Pro-D 3 Diamond Tester package includes the following items:
- GemOro Pro-D 3 Diamond Tester unit
- Micro USB cable
- AC adapter/charger
- (3) NiMH rechargeable AAA batteries
- Loose stone holder
- Compact rubberized portable storage case
- Stone Testing Cloth

Setup
- Battery Installation: Open the battery compartment and insert the three supplied NiMH rechargeable AAA batteries. Ensure correct polarity. Alternatively, you may use AAA Alkaline batteries.
- Charging (Optional): If using the rechargeable NiMH batteries, connect the Micro USB cable to the tester and the AC adapter, then plug into a power outlet. The battery LED indicator will show charging status.
- Power On: Press the power button located on the top of the tester. The unit will beep and the indicator lights will illuminate, signaling it is ready for use. It takes less than 30 seconds for the unit to power on and be ready.
- Probe Tip Protection: Remove the protective cap from the probe tip before use.

Video: GemOro Pro-D 3 Diamond Tester Overview
This video provides a brief overview of the GemOro Pro-D 3 Diamond Tester, demonstrating its key features and components.
Operating Instructions
- Clean the Stone: Before testing, always wipe the stone with the supplied Stone Testing Cloth to remove any body oil or residue, which may cause false readings.
- Hold the Tester Correctly: For accurate results, hold the tester with your fingers on the finger pads and resting on top of your hand to complete the electrical circuit.
- Test the Stone: Gently press the retractable probe tip perpendicularly onto the table (flat surface) of the stone. Ensure the metal tip is fully pushed in.
- Interpret Indicators:
- Green Light/Sound: Indicates a Diamond.
- Blue Light/Sound: Indicates Moissanite.
- Pink Light (No Sound): Indicates White Sapphire.
- Red Light/Beeping: Indicates Metal Alert (probe touching metal setting).
- Testing Unmounted Stones: Use the provided loose stone holder. Place the stone on the holder and ensure your hand makes direct contact with the holder while testing to complete the circuit.

Video: GemOro UltraTester 3+ Diamond Tester Usage Guide
This video demonstrates the operation of a similar GemOro tester, including proper handling, testing procedures, and interpretation of results for various stones.
Maintenance
- Cleaning the Probe Tip: Periodically rub the metal tip on white paper or the Stone Testing Cloth to remove body oil and oxidation buildup, which can affect accuracy.
- Battery Care: Ensure batteries are correctly oriented. If using rechargeable batteries, charge them regularly.
- Storage: Always replace the protective cap on the probe tip and store the tester in its compact rubberized portable storage case when not in use to prevent damage.
Troubleshooting
- Inaccurate Readings:
- Ensure the stone is clean and free of oils.
- Verify the probe tip is clean.
- Confirm proper contact with the stone and the tester's finger pads/loose stone holder.
- Tester Not Powering On/Charging:
- Check battery orientation.
- Ensure battery door tabs are not crushed and are making proper contact with the batteries.
- If using rechargeable batteries, ensure the AC adapter and Micro USB cable are correctly connected and functioning.
- If the battery LED indicator flashes red, it suggests incorrect battery orientation or no batteries are present.
- Metal Alert Beeping: This indicates the probe tip is touching the metal setting of the jewelry, not the stone. Reposition the probe.
Specifications
| Item Model Number | G0774 |
| Package Dimensions | 8.78 x 5.2 x 1.97 inches |
| Item Weight | 0.01 ounces |
| Power Source | Micro USB, rechargeable NiMH batteries, or AAA Alkaline batteries |
| Features | LED stone illumination, UV fluorescence detection, retractable probe tip, battery-saving auto-off function |
Warranty and Support
The GemOro Pro-D 3 Diamond Tester comes with a 2-year limited replacement warranty on the probe tip and a lifetime warranty on the electronics. For technical questions or support, please contact GemOro directly.
GemOro is a leading manufacturer of gold and platinum testers, as well as diamond, moissanite, and white sapphire testers, trusted by professionals and hobbyists alike for accuracy, reliability, and ease of use.





