Aluminum and magnesium are two elements that bear a strong resemblance to one another, mostly because one of the elements that forms aluminum is actually magnesium. Additionally, they are neighbors on the periodic table of elements indicating that they are very similar. For this reason, they can be easily confused with one another. But there are some differences that set them apart.
- Appearance and physical properties
While at first glance aluminum and magnesium resemble one another closely, if you look a little deeper there are some subtle differences. Magnesium is bit lighter than aluminum in color and appears to be a gray-white, while aluminum is closer to silver-gray.
Magnesium resides as atomic number twelve on the periodic table of elements, right next to aluminum, whose atomic number is thirteen. Given this difference, magnesium is only about one third the weight of aluminum.[i] Further, magnesium is classified as an alkaline earth metal on the periodic table. Other metals in this group are beryllium, calcium, strontium, barium and radium. Aluminum is not in this group, but is categorized as an ‘other metal,’ along with gallium, indium, tin, thallium, lead and bismuth. Magnesium is also highly flammable, and produces an intense, bright, white light when it burns. Aluminum is not considered flammable. Magnesium also reacts with water at room temperature in a process where hydrogen bubbles form slowly on the surface of the metal.[ii] Aluminum is not reactive with water either and only becomes oxidized by it when in extremely low temperatures to produce hydrogen and aluminium hydroxide.[iii]
- Occurrence in nature
Magnesium is the ninth most abundant element in the universe and the fifth most common element on Earth (after iron, aluminum, oxygen and silicon). It makes up approximately 13% of Earth’s mass and comprises a large portion of the mantle. It is also the third most abundant element found dissolved in seawater, right after sodium and chlorine. This element occurs naturally, only when in combination with other elements, frequently magnesite, dolomite and other minerals. It can also be produced artificially.
Aluminum is produced when magnesium and hydrogen fuse in large stars. It is estimated to be the fourteenth most common element in the universe, and on Earth, it is primarily found in the crust. It is the third most common element on this planet, after silicon and oxygen and is the most abundant of the metals. Aluminum is almost never found in its natural state, and is often found in oxides or silicates.[iv]
- Relationship with living things
Aluminum has no known function in biology and is usually not found in the human body unless consumed. While it is generally nontoxic, it can cause altered function of the blood-brain barrier in very high doses. It can come into contact with the body and be absorbed when using products that contain aluminum, such as antiperspirants, antacids, maltol, dyes, and food additives. It can also be absorbed when present in water, but is not considered a health risk if exposure is within normal limits.[v]
Magnesium is very different in this regard. It is actually the eleventh most abundant element by mass in the human body, and an adult usually averages about 22-26 grams with most being found in the cellular or intracellular tissue. It is thought to be essential for all cells and over 300 enzymes, including those that synthesize ATP as well as the nucleotides that synthesize DNA or RNA. A common recommended daily value would be between 200 mg and 300 mg for an average adult. It is found naturally in many different food sources, including nuts, cereal, spices, cocoa and green leafy vegetables such as spinach. Magnesium can also be added to the diet as a supplement and is commonly found in multivitamins. Magnesium deficiency is widespread, particularly in the United States where fewer than one-third of the population meets the recommended intake guidelines. Chronically low magnesium levels are associated with health conditions such as diabetes mellitus type 2, hypertension, metabolic syndrome and fasciculation.[vi]
Both aluminum and magnesium have many, many uses though they are very different. The first major difference is dependent upon magnesium’s biological importance. Due to the need for it in the human body, it can also be used as a medicine in certain situations. It is the recommended treatment for managing patients with heart arrhythmias, digoxin induced arrhythmias, and prevention of sudden cardiac death; it is also the recommended treatment for managing pre-eclampsia, eclampsia, hypomagnesemia, possible prevention of migraine and for treatment of restless leg syndrome. In addition to the medicinal applications, magnesium is also found in many consumer products such as bath salts, fertilizer, antacids, laxatives, antiseptics, sedatives, and in powder form it is used by gymnasts, weightlifters, and climbers to improve their grip and prevent their palms from sweating. In its metal form, magnesium also has applications in certain aircraft and automobile models as well as being used for photoengraving, fireworks, batteries, and the manufacturing of cell phones, laptops, cameras, tablets and other electronic devices. When compounded with other elements, it is also used in food, the manufacturing of paper and the preparation of alcohols.[vii]
Aluminum also has many applications, but none are related to a biological need. It’s primarily used in its metal form in the development of parts used in transportation devices, packaging for food and beverages, building components including siding, windows and doors, cooking utensils, baseball bats, magnets, watches, street lights, ship masts, LED lighting components, paints, pyrotechnics, the production of hydrogen gas and in coins for some countries. As a compound, aluminum can be used as an astringent, antacid, and a component in vaccines. It is also used in the production of glass, ceramics, gemstones, cosmetics, paints, paper products, and waterproof fabrics.[viii]