Here is an example of a "blackened" polish: http://www.a-england.co.uk/gothic-beauties/50-lady-of-shalott.html
Marc Jacobs Sally is a more main stream example of a "blackened" polish: http://www.beautyjunkiesunite.com/WP/2013/08/30/marc-jacobs-beauty-enamoured-hi-shine-nail-lacquer-polish-nirvana-sally-fluorescent-beige-ultraviolet-swatches/
Will do! I'll add that in the next update (probably later tonight so I can push all the changes at one time.)