The Grateful Dead frontman's guitar is called Wolf. Guernsey's auction house says it'll be offered May 31 at Brooklyn Bowl, a bowling alley, restaurant and venue for music shows.
The proceeds will go to the Alabama-based Southern Poverty Law Center .
The guitar is being sold by devoted Deadhead Daniel Pritzker. The philanthropist, musician and film director bought it in 2002 at Guernsey's for $790,000. It could exceed $1 million this time.
The auctioneer says Wolf first appeared in a 1973 New York performance the Grateful Dead gave for the Hells Angels.
Garcia played Wolf everywhere from San Francisco's Winterland Ballroom to New York's Palladium and Egypt's Great Pyramids.
The 1977 film "The Grateful Dead Movie" was directed by Garcia and features extensive Wolf footage.
Garcia died in 1995.
Copyright 2018 The Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.