LEO is a portable desktop diamond verification instrument for loose and mounted stones, designed to separate diamonds from synthetic diamonds and diamond simulants. Leo is manually operated but gives an automatic test result.

The Leo was purchased by the Natural Diamond Council and independently tested.

Stone Testing Capability

Weight: 0.01 ct-12 ct
Colour: D-M
Diamond Simulants: Yes
Mounted Stones: Yes (open back settings, not yet ASSURE Tested)

Instrument Performance

The below results demonstrate the performance of the LEO with the ASSURE Core Sample:

Diamond False Positive Rate (optimal rate 0%): 4.6%
Diamond Referral Rate (optimal rate 0%): 3.7%
Diamond Accuracy Rate (optimal rate 100%): 51.6%
Speed (stones tested per hour): 219

The ASSURE Core Sample consists of 1,000 loose diamonds, 200 loose synthetic diamonds and 200 loose diamond simulants. The stones are 0.02ct to 0.20ct in D-J colour.

Instrument Capabilities

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: N/A

The instrument tests individual stones and automatically one of the following results:

  1. Earth mined
  2. Type II
  3. Simulant
  4. Cubic Zirconium
  5. Moissanite

 The ‘Type II’ result could contain potential synthetic diamonds and diamonds. These referrals should be tested further for full verification.

Contact information

ASSURE Tested March 2019