As a (hopefully still in time) last minute contribution to Celestia Day 2019 of Equestria Daily I made a mosaic of Celestia of stones and a little golden tinfoil wrapping. While I am pretty sure that given enough time and money to travel one would likely be able to find natural Celestia colored stones I got to admit I took a bit of a shortcut this time and bought some artificially colored stones so I think only the white and black ones are in the color that nature itself provided.  
This image was taken with a color enhancing filter. I’m going to upload a few other versions of this image taken with different filters / camera settings.