Attached Link: Example gem shine (nudity)

This i made in PP2012 and I duplicated the prop took 1 prop for the normal material with visible in camera and the other used as a lightemitter (properties check lightemitter and in the material set the ambient value high and unchecked visible in camera). So one get one normal prop and the shine of the other without overpowering the material in itself if you don't want the ambient blow everything out.

In P8 however one can still use the ambient in the material of the sparkle to emit light, but how higher the ambient and the shine on the environment the more likely that the gem will be overpowered by the ambient and fall flat.
My solution would be 2 renders, 1 with the normal material and one render with a high ambient in the existing material and photoshop the normal gem on top of the overblown one.

With both IDL is required.

Another option is to make a new light add the sparkle material to the light and position the light just above the gem.

Hope this helps!

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