On March 2, 1996, at 1013 hours Pacific standard time, a Cessna 150G, N8662J, sustained a collapsed main landing gear and wing contact to the runway during a loss of control in the takeoff ground roll at the Auburn, California, airport. The aircraft was owned and operated by the pilot and was beginning a local area personal flight. Visual meteorological conditions prevailed at the time and no flight plan was filed. The aircraft sustained substantial damage. The certificated commercial pilot and his one passenger incurred minor injuries. The aircraft is a conventional landing gear conversion under an approved STC. The pilot reported that during the takeoff ground roll, he lost directional control when he raised the tail at 40 mph. The aircraft veered right off the runway. During the pilot's attempts to turn back to the runway, the left main landing gear contacted a large rock imbedded in the ground. The gear strut then separated from the aircraft and the left wing contacted the ground.