"Algoma Jade," Green Lorrain Quartzite, from Echo Lake, Sault Ste. Marie.
Quartzite is a metamorphic rock formed from the sedimentary rock, sandstone. The quartz sand grains were cemented together by heat and pressure.
Green Lorrain Quartzite is coloured green by fuchsite (sericite; muscovite) due to the presence of chromium derived from detrital chromite, which was weathered from komatiitic rocks of the Abitibi greenstone belt.
The Abitibi greenstone belt is a 2,800 - 2,600 million year old greenstone belt is formed of igneous and sedimentary rocks and hosts gold mines in Ontario and Quebec.
A photo of a polished specimen of "Algoma Jade."