I have been struggling for years to get accurate photos of gemstones.  I have recently made some breakthroughs, one of which is just take the photos out in sunlight, direct sunlight, most of the time.  The image you see depends on many factors:

1 Direct or diffuse illumination-  For some gemstones, direct illumination gives such a bright "glint", that the camera does not readily get the color correct, I believe because what one is really seeing is a partial image of the sun, i.e. yellowish.  With diffuse outdoor illumination, the color is better, because not only are we getting the yellow from the sun, but also, a lot of blue scattered light.  This helps greatly in getting some of our purple/lavender gem colors correct.

2 Indoor or outdoor-  The sky conditions do not allow one to take all of their photos outdoors.  Indoor photos are affected greatly by the light source(s).  We have Incandescent, LEDsFluorescent.  Incandescent is quite red, and the lavender gemstones (which photo well on a bright sunny day), the color is far off taken indoors.  The attached photos show the difference in color for indoor (tray), and next blog, and outdoor (individual gemstone, following blog).  Some of the difference can be improved by processing adjustments, but there is nothing like a bright sunny day to get the lavender colors correct.

3 Color of the gemstone-  Some gemstones seem to give good images under a wide variety of conditions.  For example, Fordite, which is paint, comes out nice and accurate quite easily.  Others, the lavenders for example, are much more difficult.

4.  Camera and screen settings-  No matter what the gemstone, the illumination, some of the gemstone colors are difficult and some are easy.  But in the end, what ever is done with them, the screen setting on the monitor can either get it right or mess it all up.  

SO, I will strive to get improved photos, display different ones under conditions of illumination, as above, BUT, if in the end the gemstone that you get is not the color you hoped for, you can return it for a full refund.