Instructor: Branko Deljanin, B.Sc., GG, FGA, DUG (CGL-GRS Lab, Canada)
Audience: For gemmologists, appraisers, and individuals with trade experience
Date: Jan 19, 2019 (Saturday)
Location: San Francisco
9am-12:45pm: ID of Colourless Diamonds (Natural, Treated, and Lab-grown)
- Colourless Natural diamonds: sources, characteristics and identification
- Methods of growing HPHT and CVD diamonds
- Inclusions in Natural and Synthetic diamonds
- UV lamp – reaction of different diamonds, loose and mounted with “PL / Jewellery inspectors”)
- CPF (Cross Polarized Filters) method and to screen and ID diamond’s origin
- Clarity and Color Enhancements – unstable (Fracture Filling and coating),
- Clarity Enhancements – stable (Traditional Lasering, KM Laser drilling)
- Post treatments of CVD-grown colorless diamonds (HPHT)
- ID of HPHT-enhanced diamonds using advanced instruments
- ID of mounted synt. diamonds with EXA instrument and screening instruments
- Problems and solution in identification of melee natural and synthetic diamonds
PRACTICAL WORKSHOP: Samples of Ia, IIa, IIb, Ib diamonds (natural and synthetic origin) are tested with mini UV lamp (“PL inspector”), microscopes with mini Polarioscope
1:45pm-5:30pm: ID of Coloured Diamonds (Natural, Treated, and Lab-grown)
- YELLOW and ORANGE diamonds: sources/producers, characteristics and ID
- GREEN and CHAMELEON diamonds: source/producers, characteristics and ID
- BLUE and GRAY diamonds: sources/producers, characteristics and ID
- PINK and RED diamonds: sources/producers, characteristics and ID
- Use of Standard Instruments to separate Coloured Natural and Synthetic Diamonds
- Color Enhancements – stable (irradiation, annealing, HPHT, multistep treatments)
- Post treatments of HPHT-grown and CVD-grown diamonds (irradiation and HPHT)
- Identification methods for treated diamonds with advanced instruments at labs
- Grading and Certification of coloured diamonds at gem laboratories
PRACTICAL WORKSHOP: Coloured Diamonds are tested with portable polarioscope, PL Inspector, microscope and handheld spectroscope in screening and identification.