OTi by Presidium is a portable diamond verification instrument for loose and mounted stones designed to separate natural diamonds from synthetic diamonds and diamond simulants. It has a dual-probe tip that measures thermal conductivity and UV light absorption to determine stone type. OTi is manually operated but gives an automatic result on its built-in display.
Weight: 0.06 ct+
Size: 2.60 mm +
Colour: D-J
Shape: All
Diamond Simulants: Yes
Mounted Stones: Yes
Key performance metrics measured for the OTi with the ASSURE 2.0 Primary Loose Stone Sample:
Diamond False Positive Rate (optimal rate 0%): 0%
Diamond Referral Rate (optimal rate 0%): 7.2%
Diamond Accuracy Rate (optimal rate 100%): 92.8%
A subset of the Primary Loose Stone Sample with minimum table width of 1.6mm (2.6mm girdle diameter) was tested three times and consists of 167 loose diamonds, 66 loose synthetic diamonds and 30 loose diamond simulants. The stones are 0.06 ct to 0.20 ct in D-J colour.
The measured test speed for the OTi was 239 stones per hour.
Key performance metrics measured for the OTi with the ASSURE 2.0 Primary Mounted Stone Sample:
Diamond False Positive Rate (optimal rate 0%): 0%
Diamond Referral Rate (optimal rate 0%): 6.8%
Diamond Accuracy Rate (optimal rate 100%): 93.2%
The Primary Mounted Stone Sample consists of jewelry pieces with open-back settings. The subset of the sample with minimum table width of 1.6mm numbers 137 stones. The stones are a mix of diamonds, laboratory grown diamonds and diamond simulants in the D-J colour range and have a minimum girdle diameter of 2.6 mm.
Automated Feed: No
Automated Results: Yes
Automated Dispense: No
Detect or Refer (Synthetic Diamonds): Refer*
Detect or Refer (Diamond Simulants): Detect
Multiple Stones at Once: No
Training Required: No (User manual provided with device)
* stones classified as CVD/HPHT/Type IIa are considered referrals and should be submitted for further testing.
The probe tip should be held at an upright position 90 degrees perpendicular to the table of the gemstone. The user then fully depresses the tip applying constant pressure for the duration of the testing bar shown on the screen. User must always ensure the probe tip is kept clean, and when necessary it should be cleaned as per procedure in the User Manual.
The instrument makes a measurement and displays one of the following results:
Stones classified as CVD/HPHT/Type IIa are considered referrals and should be submitted for further testing.
Size: 7.0 cm (W) x 10.5 cm (D) x 2.5 cm (H)
Weight: 0.11 kg
Price: 1,449 USD (July 2025)
presidium.com.sg
sales@presidium.com.sg
+65 6771 9760
ASSURE Tested July 2025
