This is what I found on NBCNews.com:

Grunge became gold Saturday as the guitar Kurt Cobain played on Nirvana’s 1993 “MTV Unplugged” performance months before his death sold for an eye-popping $6 million at auction.

The 1959 Martin D-18E that Cobain played in the band’s rare acoustic performance and subsequent live album was sold to Australian Peter Freedman, owner of Røde Microphones, at the Music Icons event run by Julien’s Auctions in Beverly Hills, California.

Cobain used it to play tunes including “About a Girl” and “All Apologies” at the Nov. 18, 1993 show in New York that came less than five months before the singer and songwriter died at age 27.

After opening at $1 million, the final sell price of the guitar ended up breaking several world records,” NBC News reports. For comparison, a custom guitar played by Prince “at the height of his stardom in the 1980s and 1990s” sold the day before the Cobain item, Prince’s guitar sold for $563,500. The same day, Elvis Presley’s macrame belt, worn by the iconic singer around 30 times on stage, sold for $298,000 (nearly 10 times its expected price) while an ivory dress Madonna wore in her 1990 “Vogue” video sold for $179,200.

Information provided by NBCNews.com.