The pyrophoricity of hydrides and oxides forming on the surface of plutonium can cause it to look like an ember under certain conditions. A pyrophoric substance (from Greek πυροφόρος, pyrophoros, fire-bearing) ignites spontaneously in air at or below 55 °C (130 °F).
https://en.wikipedia.org/wiki/Pyrophoricity
Magnesium compounds are used medicinally as common laxatives, antacids (e.g., milk of magnesia), and to stabilize abnormal nerve excitation or blood vessel spasm such as in eclampsia.
https://en.wikipedia.org/wiki/Magnesium
Many scientist disagree on what causes this violent reaction to water, but the most recognized answer is: (In simple terms). When heated magnesium ignites and burns with an intense white light and releases extreme amounts of heat. Most magnesium fires cannot be extinguished by water, since water reacts with hot magnesium and releases hydrogen.
http://www.midsouthrescue.org/id21.html
In commerce, the chief use for the metal is as an alloying agent to make aluminium-magnesium alloys, sometimes called magnalium or magnelium. Since magnesium is less dense than aluminium, this alloy is prized for its properties of lightness combined with strength.
https://en.wikipedia.org/wiki/Magnesium
Examples are iron sulfide and many reactive metals including uranium, when powdered or thinly sliced. Pyrophoric materials are often water-reactive as well and will ignite when they contact water or humid air. They can be handled safely in atmospheres of argon or (with a few exceptions) nitrogen.
https://en.wikipedia.org/wiki/Pyrophoricity
Example of Mag. Fire. Magnesium is some what like wood, in that the smaller the particles, the easier it is to ignite. But unlike wood, magnesium must have its complete surface area heated in order to ignite.
http://www.midsouthrescue.org/id21.html
The Mg2+ cation is the second-most-abundant cation in seawater (occurring at about 12% of the mass of sodium there), which makes seawater and sea-salt an attractive commercial source of Mg. To extract the magnesium, calcium hydroxide is added to seawater to form magnesium hydroxide precipitate.
https://en.wikipedia.org/wiki/Magnesium
Magnesium ions are sour to the taste, and in low concentrations they help impart a natural tartness to fresh mineral waters. Magnesium is the metallic ion at the center of chlorophyll, and is a common additive to fertilizers.
https://en.wikipedia.org/wiki/Magnesium
Magnesium is the eighth-most-abundant element in the Earth's crust by mass and tied in seventh place with iron in terms of molarity. It is found in large deposits of magnesite, dolomite, and other minerals, and in mineral waters, where magnesium ion is soluble.
https://en.wikipedia.org/wiki/Magnesium
Click picture to enlarge. Many scientist disagree on what causes this violent reaction to water, but the most recognized answer is: (In simple terms) When heated magnesium ignites and burns with an intense white light and releases extreme amounts of heat.
http://www.midsouthrescue.org/id21.html
what ignites magnesium
Intense white light ignites Magnesium. The intense white light ignites magnesium. Intense white light ignites magnesium.