"The ignition temperature of massive magnesium is very close to its melting point of 650 degrees C (1,202 degrees F). (See Table 2.) However, ignition of magnesium in certain forms may occur at temperatures well below 650 degrees C (1,200 degrees F). For example, magnesium ribbons and shavings can be ignited under certain conditions at about 510 degrees C (950 degrees F), and finely divided magnesium powder can ignite below 482 degrees C (900 degrees F)."