Green obsidian, Helenite. Two sizes available, emerald cut. 5 ct - 12 x 10 mm 6.5 ct - 14 x 10 mm
"Helenite, also known as Mount St. Helens obsidian, emerald obsidianite, and ruby obsidianite, is an artificial obsidian made from the fused volcanic rock dust from Mount St. Helens. Helenite was first created accidentally after the eruption of Mount St. Helens in 1980. Workers from the Weyerhaeuser Timber Company were attempting to salvage equipment damaged after the volcanic eruption. 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, transformed the volcanic particles into a compound that would be later commercially replicated as helenite.
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). Although helenite and obsidian are both forms of glass, helenite differs from obsidian in that it is man-made."
"Obsidian forms from molten lava in the last stages of volcanic eruptions, the remaining silica minerals that flow onto the surface and are super-cooled into glass before crystallization can occur. It is an amorphous material known as a “mineraloid” with a hardness of 5 to 5.5... Latin obsidianus, meaning “the stone of Obsius,” the prominent Roman who discovered it. It is also referred to as “volcano glass,” “mirror of the Incas,” and “Iceland agate.” [www.mindat.org][geology.com][www.britannica.com][Simmons, 280][Lecouteux, 239][Megemont, 132][Dictionary