I was assigned the task of a mockup to put some gems into a skull cufflink for a customer to review, the task is simple.  extract the gem from a previous product using Pen Tool, make a new layer and match it into the eye socket of the new one.  For different colors, simply use Hue/Satiation (CMD+U) option to instantly change gem’s hue.

Here is the image of the original products I worked on:

And finished job: