Ackermand et al.(2006): Lazulite-bearing metaquartzite of the Itremo Group (Central Madagascar); Scientific significance and economic importance in Proceedings of the Malagasy-German Research Cooperation in Life and Earth sciences, 5-18
The fastest fighter aircraft is the MiG 25, with speeds topping at Mach 3.2 (2,450 mph/4,000 km/h). Pilots were not allowed to go beyond Mach 2.8. Above Mach 2.8, the engines would overheat and burn up.
The unofficial record for fastest piston-engined aeroplane (not in level flight) is held by a Supermarine Spitfire Mk IXX, which was calculated to have achieved a speed of 690 mph (1,110 km/h, Mach 0.96) in a dive on 5 February 1952.