By Claudia Assis
SAN FRANCISCO (MarketWatch) -- Gold and crude-oil futures tanked on Tuesday as investors continued to react to news Greece has called a referendum on its rescue plan, rehashing default fears. Gold for December delivery GC1Z -1.88% declined $37.40, or 2.2%, to $1,686 an ounce on the Comex division of the New York Mercantile Exchange. Oil also for December delivery CL1Z -3.20% declined $3.47, or 3.7%, to $89.83 a barrel on the Nymex. Greece on Monday called for the referendum in the face of anger over the austerity plan.