Aluminum is the most abundant metal in the earth's crust. Over 8% of the crust is aluminum; iron comes in second at about 5-1/2%. Aluminum is a lot lighter than iron, melts at a lower temperature, is softer, and doesn't rust. Okay, it does oxidize, though - which is what makes iron rust - but instead of turning red and flaking off, aluminum oxide is white and powdery. Unlike iron, which is highly oxidizable when exposed to water, aluminum resists water corrosion.
Aluminum is highly ductile. This means it can be deformed by stretching. It can be stretched by more than 50% of its original length if it is dead soft. Stretching is an amazing property that allows a material to be pulled thinner without breaking. In our class, though, ductile processes are not as common as malleable processes. Malleable means the material can be compressed without breaking. Aluminum is highly malleable, and can be easily hammered, rolled, or pressed.
Because of its abundance, aluminum is inexpensive. Combined with its inherent malleability, ductility, and resistance to corrosion, it is the metal of choice for many projects. Besides, it is shiny white and pretty! It is incredibly reflective; better than silver.
Copper would be second on the list of metals for use in metal forming because of its workability and durability. Typically, using copper would be at your own expense due to its cost, and the final product would be much heavier and harder to work.
Virtually all aluminum mined on the planet has to be extracted from an ore, meaning pure blobs of aluminum do not exist, and the metal was not discovered until a periodic table of elements was theorized... and guess what? There was a blank spot where a #13 element ought to be (aluminum). Copper, silver, and gold had been discovered millennia ago because pure blobs could be found in riverbeds and hillsides. Before aluminum was discovered, the other three metals were the materials of choice for artistic forms. Interestingly, when aluminum was first discovered and isolated, the industry tried to sell it as a rare and precious metal for jewelry and the like, but the populace could not equate its light weight with financial value. Heavier things seem more valuable to the average person.
Aluminum oxidizes. Although aluminum-oxide can form a protective layer, in typical circumstances such as in the presence of electricity and water, this oxide layer will not protect the underlying metal, and the entirety of the aluminum can dissolve into a white powder through galvanic reaction. In nature, the conditions for aluminum being oxidized or combined with other elements is essentially 100%.
Iron oxidizes easily and heavily. As it does, it flakes away until the eitirety of the metal is dissolved. Solid chunks of iron have historically only been found on earth in the form of meteors.
Copper and silver also oxidize easily, but these oxide layers do not flake or powder; instead, these layers form a sealed surface, preventing further oxidation or corrosion.
Amazingly, pure gold does not oxidize because it does not react easily with oxygen. It has been a metal of choice for eons becuse it could be found sitting in lumps in river beds, and easily formed. Oddly, gold is incredibly rare, so rare that the entire volume of all of the gold ever mined would fill the first floor of Analy Hall! By the way, nearly half of all gold mined is now in the form of jewelry. Gold would be an amazing material to work with if it was not so rare.
Pure aluminum is hard to find, as it is most useful in the form of alloys (chemically combined with other elements) because of various properties related to the needs of industry. Like the other metal elements listed on this page, because it is an element, aluminum is essentially infinitely recyclable. If it is heated and melted, it will still remain aluminum. Alloys are not infinitely recyclable, as the melting process may disassociate the constituent elements, or evaporate some away. However, adding back the proper alloyed materials is easily achievable.
As mentioned earlier, aluminum is incredibly common on Earth, followed only by iron.
Other metals that are highly malleable include copper (0.0006% of the Earth's crust), silver (0.0000075% of the Earth's crust), and gold (0.000004% of the Earth's crust). Copper is quite rare in comparison to aluminum, but quite abundant compared to silver and gold! Aluminum is much lighter than the other three. Gold, however, takes the gold for most malleable. It is the most malleable metal known - by a long shot. Gold can be flattened to mere atoms thick, and is ductile enough to be stretched to one atom in diameter.
