Turquoise is an opaque, blue-to-green mineral that is a hydrous phosphate of copper and aluminium, with the chemical formula CuAl6(PO4)4(OH)8ยท4H2O. It is rare and valuable in finer grades and has been prized as a gemstone for millennia due to its hue.
Turquoise
"Big Blue", a large turquoise specimen from the copper mine at Cananea, Sonora, Mexico
Massive Kingman blue turquoise in matrix with quartz from the Mineral Park mine, Arizona, US
Turquoise of Madan-e Olya of Nishapur
Blue-green is the color between blue and green. It belongs to the cyan family.
A sample of turquoise
Green-winged teal (male)
Teal iceberg
A lake was colored blue-green by glacial flour.