Green Quartzite

Quartzite forms when quartz-rich sandstone or chert is recrystallized by the heat and pressure of metamorphism, most often during mountain building at convergent plate boundaries. Green fuchsite-bearing quartzite is quarried as decorative stone, for example in the Elmers Rock Greenstone Belt of Wyoming, USA; IGS lists Spain, Russia, India and Chile as sources of quartzite and aventurine.

Quartzite breaks through its quartz grains rather than around them, which separates it from sandstone. Dyed green quartzite is a known jade imitation: in GIA Gem Trade Lab Notes, green beads offered as jade and as aventurine gave a refractive index of 1.55 and showed a quartzite structure, with dye visible in cracks under magnification and coming off on an acetone-moistened cotton swab; some well-dyed beads closely resembled fine chrome-green jadeite to the unaided eye, but their refractive index and spectroscope evidence of dye proved their identity. Jadeite has a refractive index of about 1.66 to 1.69 and a specific gravity of about 3.34.

Quartzite has a Mohs hardness of about 7 and is very tough. IGS lists no special care for quartz but notes that some dyes used on quartz fade, and the GIA lab found that dye in dyed quartzite beads came off with acetone, so dyed pieces should be kept away from solvents.

Green quartz-based stones have long been sold as jade substitutes: GIA's 1982 survey of jade simulants lists aventurine quartz among them, and IGS lists "Indian jade" as a misnomer for green aventurine quartz. The Japanese retailer Pascle adds, as a trade account, that because India was the main source green quartzite also circulated as "Indian jade", and that dyed quartzite is still sold under names ending in "jade".

The Japanese retailer Pascle writes that quartzite, being an aggregate of small quartz grains, is regarded as a symbol of harmony and is said to support kindness and communication with others, and that green quartzite is said to ease tiredness of body and mind.