PRESIDIUM PRIM II Manual Del Usuario página 17

Synthetic Spinel/Synthetic Sapphire and High Zircon/
GGG have overlapping Reflectivity Index. If performing
a second test using the Presidium Gem Tester for further
separation, the results indicated will be as follows:
• Synthetic Sapphire: needle goes to a high position in
the red zone.
• Synthetic Spinel: Needle goes about halfway into the
red zone.
• High Zircon: Needle goes 2/3 into the red zone.
• GGG: Needle goes 1/3 into the red zone
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