Each image has to be colour corrected individually. Diamond surrounded by gold will appear to have warm colour as compared to a diamond with platinum or silver surround. This is because the surrounding colour is casting its colour on the diamond. Thus Rubies, emeralds, topaz and diamonds when fixed into a same area can play havoc. Colour from the backgrounds can very easily contaminate the colour of the product. This is the reflection of the background. Sometimes it adds environment and is very interesting, but sometimes it needs to be removed. It all depends from case to case.
At this stage sometimes you are required to produce different images of different coloured diamonds of the same piece for the library. Similarly the same piece of jewellery can represent different metal options, from gold to platinum to rose gold.
This can be done.