Most good cameras will have an option to auto colour balance and this will work on many occasions. But not always. If you are using normal household incandescent lamps, you could end up with a yellow colour cast. If this occurs, and your camera can't resolve, then you will need to fix through Image Editing software.
I have found that my Sony has difficulty getting purple amethyst looking right, as well as the usual suspects such as dioptase. Fortunately, my Canon camera seems to handle most minerals well.