Welcome back! Today we present our third and final primer on our most-used metals. We close out the series with aluminum. That’s al-YOU-min-ium for our British readers. Unlike bronze or brass, aluminum is an honest-to-goodness element, atomic number 13, in the boron group. There it is. It is the third most abundant element in the earth’s crust after oxygen and silicon, but is so reactive that finding it naturally occurring in its elemental state is exceedingly rare. Instead,