Helenite

Using acetylene torches, they noticed that the intense heat was melting the nearby volcanic ash and rock and turning it a greenish color.

The silica, aluminium, iron, and trace amounts of chromium and copper present in the rocks and ash in the area, combined with the heat of the torches, transformed the volcanic particles into a compound that would be later commercially replicated as helenite.

[3] As word of the discovery spread, jewelry companies took note and began to find ways to reproduce the helenite.

Helenite is made by heating rock dust and particles from the Mount St. Helens area in a furnace to a temperature of approximately 2,700 °F (1,480 °C).

The stone has been marketed by the jewelry industry because of its emerald-like color, good refractive index, although its durability is low.