"Black diamond" is a term used in American ski resorts to designate a steep slope or one which involves challenging terrain. So called because the marker signs show a black diamond (lozenge) shape on a white background.
Black Diamond is the debut album from American R&B/soul singer Angie Stone, released on September 28 1999 in the United States via Arista Records (see 1999 in music).
"Black Diamond" is a song by Kiss credited to Paul Stanley, even though it is said that it was co-written with Gene Simmons http://www.kissfaq.com/discography/kiss.html.