I know all the shades of grey... anthracite many from memory... 

Anthracite is darker than slate grey yet lighter than black grey.  In this shade we have a £29.99 flash sale on our duroplast soft close, quick release toilet seat:

https://www.replacementtoiletseats.co.uk/ourshop/prod_6868211-RTS-Anthracite-Dark-Slate-Grey-Duroplast-Soft-Close-Toilet-Seat-w-Quick-Release-84336.html

Check it out quick, before this sale runs coal...