Elements isolated with the aid of potassium and sodium

Zirconium minerals are widely distributed in Nature, and have been used for centuries. In his enraptured description of the four-square city, Saint John the Divine mentioned the jacinth (or hyacinth) as one of the twelve precious stones that garnished the foundations of the city wall (14). 

Although zircon was frequently used by the ancients for intagli, and although hyacinth and jargon were well known in the Middle Ages, the presence in these minerals of an unknown metal was not suspected until near the end of the eighteenth century. The earth zirconia was overlooked because of its great similarity to alumina, and it took the analytical skill of a Klaproth to detect it. 

In 1787 Johann Christian Wiegleb analyzed a zircon from Ceylon and reported only silica, with small amounts of magnesia, lime, and iron (54). Only two years later, Klaproth discovered the earth zirconia in a j argon, 

Baron Louis-Bemard Guyton de Morveau, 1737-1816. French attorney and chemist. Professor of chemistry at the Ecole Polytechnique from 1794 to 1815. With Lavoisier, Fourcroy, and Berthollet he brought chemical nomenclature into accord with modern views on combustion. He made the first serious researches On the structure of steel. 

When Klaproth analyzed the same specimen he found  

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Other elements isolated with the aid of potassium and sodium... 

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