Beryl, the main source of Beryllium, is chemically identical to Emeralds.  Beryl and Emeralds are both Beryllium Aluminum Sulfate.  In 1798 M.L. Vaquelin recognized the element in both beryl and emeralds.  Thirty years later, in 1828, Friedrich Wohler isolated Beryllium by the reaction of potassium on BeCl₂ in a platinum crucible.

Thus making the equation

2K+BeCl₂ --> 2KCl+Be