http://wiki.spiralknights.com/images/c/cb/Chroma_mask-fix.jpg
I didn't know it was that uncommon, so I didn't notice exactly where I found it.
I know it was in a prize crate, and it was below Emberlight. I'm thinking depths 25-30, because I feel like it was close to the core, but it could be anywhere around those parts.
I realized it probably was a big deal when people wanted to take screenshots of themselves standing next to me.
I think you might need to move your image to your user page on the wiki - as we aren't supposed to host images outside of the wiki.
But yeah - it looks awesome! And I have heard of some rare drops, but usually they are rare enough that one one person has them so far!