Check your phone settings and see if you have any filters or other settings that will adjust the tone of the image - look for something like a warm filter (red based), with purples, sometimes I had better luck with the cool filter (blue-based), even though it was coming up as too blue already.
If you can edit them on a PC, try using Windows Gallery or PhotoFiltre (both free) to adjust the colours - Windows Gallery is pretty simplistic, and you can adjust colours with temperature and hue, and PhotoFiltre is a little more advanced but the effects are more dramatic, so I tend to find something that works well in WG for one photo won't work as well in PF for the same image, and vice versa.
Often, I'll take the image on a white backgroud, adjust the colours on the computer so that the item itself looks right, then touch up the background of the image to make it white again in PicMonkey (free online tool for the basic stuff, can also be used to edit colours, temperatures etc if needed).
If you're still at a loss, feel free to send me a pic to see if I can do anything with it - I used to touch up pics sometimes for another seller a while back, no guarantees, my skills are still pretty basic 
but I'm happy to give it a shot anyway.
Thank you everyone for your wonderful suggestions! I'll give them all a go and see how I go. If I can't get it to work, I'll hold off listing them until I get my tax back and get my new camera (I pay second job tax on purpose to ensure I get a good return every year). Even if my old digital still worked, it would be no good for what I want because I need to use macro for these items and that camera didn't have macro. Normally my phone takes exceptional photos, it's only these 2 things I'm having issues with. Interestingly, I photographed and listed larger purple items (amethyst and ametrine) and the colours were spot on, so not sure what's up with these 2 things, give that one of them is an amethyst cut stone.
