Characteristics:a silvery-white, low density, reasonably strong metal that tarnishes in air to form a thin oxide coating.its alloys have very good corrosion resistance and good high temperature mechanical properties.
Properties:a ductile, silver-white, chemically active metal with a hexagonal close-packed crystalline structure. It is malleable when heated.
Magnesium is used in both its pure form and as an alloy. Depending on the composition of the metal, there can be notable differences in many physical properties. The data below is primarily regarding pure magnesium however several common alloys are also included in the data and will be noted accordingly.  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. 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. Organic magnesium compounds (Grignard reagents) are important in the synthesis of organic molecules. Magnesium compounds such as the hydroxide (milk of magnesia, Mg(OH 2)), sulfate (Epsom salts), chloride and citrate are used for medicinal purposes. Organic magnesium compounds (Grignard reagents) are important in the synthesis of organic molecules. Magnesium compounds such as the hydroxide (milk of magnesia, Mg(OH 2)), sulfate (Epsom salts), chloride and citrate are used for medicinal purposes.  Characteristics: Uses: Magnesium is a silvery-white, low density, reasonably strong metal that tarnishes in air to form a thin oxide coating. Magnesium and its alloys have very good corrosion resistance and good high temperature mechanical properties. The metal reacts with water to produce hydrogen gas. When it burns in air, magnesium produces a brilliant white light. The brilliant light it produces when ignited is made use of in photography, flares, pyrotechnics and incendiary bombs. Magnesium compounds such as the hydroxide (milk of magnesia, Mg(OH 2)), sulfate (Epsom salts), chloride and citrate are used for medicinal purposes. Magnesium. Chemical element, metallic, symbol Mg, situated in group IIa in the periodic table, atomic number: 12, atomic weight: 24,312. Magnesium is silvery white and very light. Its relative density is 1,74 and it’s density 1740 kg/m 3 (0.063 lb/in 3 or 108.6 lb/ft 3). Magnesium is known for a long time as the lighter structural metal in the industry, due to it’s low weight and to it’s capability of forming mechanically resistant alloys. Magnesium in the environment. Magnesium is the eighth most abundant element and constitutes about 2% af the Earth's crust by weight, and it is the third most plentiful element dissolved in seawater. Properties. Magnesium is a ductile, silver-white, chemically active metal with a hexagonal close-packed crystalline structure. It is malleable when heated. Magnesium is one of the alkaline-earth metals in Group 2 of the periodic table. It reacts very slowly with cold water. It is not affected by dry air but tarnishes in moist air, forming a thin protective coating of basic magnesium carbonate, MgCO 3 ·Mg(OH). .  Chemical and Physical Properties of Magnesium. Magnesium is one of the most important elements that is present in many compounds as well as alloys. It is widely used as a chemical reagent, desulfurization agent, and vital ingredient in fireworks. It finds multiple applications due to its unique chemical and physical properties. As mentioned in the chemical properties, magnesium is also present in many other compounds like dolomite, magnesium carbonate (that is also known as magnesite), and magnesium sulfate (which is also known by the name epsomite). 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. 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. It has an empirical formula of Mg O and consists of a lattice of Mg 2+ ions and O 2− ions held together by ionic bonding. Magnesium hydroxide forms in the presence of water (MgO + H 2 O → Mg(OH) 2), but it can be reversed by heating it to separate moisture. 
http://www.intlmag.org/magnesiumbasics/physical.cfm https://en.wikipedia.org/wiki/Magnesium http://www.lookchem.com/Periodic-Table/Magnesium/ http://www.chemicool.com/elements/magnesium.html http://www.lookchem.com/Periodic-Table/Magnesium/ http://www.lenntech.com/periodic/elements/mg.htm http://www.infoplease.com/encyclopedia/science/magnesium-properties.html http://www.buzzle.com/articles/chemical-and-physical-properties-of-magnesium.html https://en.wikipedia.org/wiki/Magnesium https://en.wikipedia.org/wiki/Magnesium_oxide
what is properties or characteristics of magnesium