The colors of rubies and emeralds are so striking that they define shades of red and green—ruby red and emerald green. But have you ever wondered how they get those colors?

This table, like all attempts to reduce the basic phenomena of nature to a simple pattern, falls somewhat short of its objective. For one thing, there are variations in the sequence of elements ...

If you are intimidated by the periodic table, then this introduction through the first column of elements will give you a feel for how and why the elements are arranged in this order.