Geolog Eight, I've read about black, pink (I know why), etc., so this is definitely the one.]
Olga Novikova, Black beaches are not uncommon in volcanic zones. They exist in Hawaii, Spain (Tenerife), and here in Kamchatka. This one is on Iturup. On the right (out of frame) is the Atsonupuri volcano – only the very beginning of the slope is visible.