Blue Purple Red: Amethyst Crystals
Taken in the macro mode, this is a section of an amethyst vug. It is broken into a large chunk about 2' long and 18" wide. This image was captured inside a tent where the dealer displayed his specimens for sale. There is a fair amount of dust on the chunk of crystals but the available light from about 15' away still gave enough light play to show how this common crystal displays rich coloring in the spectrum of blue to purple to red.
Here is a specimen I own of very tiny amethyst crystals called "druzy":
www.flickr.com/photos/cobalt/591176070/
And here is what a large vug looks like: