Turquoise

Turquoise is an opaque, blue-to-green mineral that is a hydrated phosphate of copper and aluminium, with the chemical formula CuAl₆(PO
4)₄(OH)₈·4H
2O. It is rare and valuable in finer grades and has been prized as a gem and ornamental stone for thousands of years owing to its unique hue. In recent times, turquoise, like most other opaque gems, has been devalued by the introduction of treatments, imitations, and synthetics onto the market.

The substance has been known by many names, but the word turquoise, which dates to the 17th century, is derived from the French turques for "Turks", because the mineral was first brought to Europe from Turkey, from mines in the historical Khorasan Province of Persia.Pliny the Elder referred to the mineral as callais and the Aztecs knew it as chalchihuitl.

Properties of turquoise

The finest of turquoise reaches a maximum hardness of just under 6, or slightly more than window glass. Characteristically a cryptocrystalline mineral, turquoise almost never forms single crystals and all of its properties are highly variable. Its crystal system is proven to be triclinic via X-ray diffraction testing. With lower hardness comes lower specific gravity (2.60–2.90) and greater porosity: These properties are dependent on grain size. The lustre of turquoise is typically waxy to subvitreous, and transparency is usually opaque, but may be semitranslucent in thin sections. Colour is as variable as the mineral's other properties, ranging from white to a powder blue to a sky blue, and from a blue-green to a yellowish green. The blue is attributed to idiochromatic copper while the green may be the result of either iron impurities (replacing aluminium) or dehydration.

Turquoise (disambiguation)

Turquoise is a gemstone.

Turquoise may also refer to:

Turquoise (song)

"Turquoise" is a song written and recorded by British singer-songwriter Donovan. The "Turquoise" single was released in the United Kingdom on October 30, 1965 through Pye Records (Pye 7N 15984) and charted, peaking at No.30. The "Turquoise" single was backed with "Hey Gyp (Dig the Slowness)" and only released in the United Kingdom. "Turquoise" was released as the b-side on "To Try for the Sun" in the United States. Interesting use of vibes in that song, played by

"Turquoise" marked a significant drop-off in Donovan's UK chart success compared to the top 10 successes of "Catch the Wind" and "Colours" and the "Universal Soldier" EP. While "Catch the Wind" and "Colours" have appeared in various formats throughout Donovan's catalogue, live versions and re-recordings of "Turquoise" are conspicuously absent.

The relative lack of success in the United Kingdom was most likely the reason leading to Hickory Records selecting "You're Gonna Need Somebody on Your Bond" as Donovan's next single in the United States. Hickory Records later released "Turquoise" as the b-side to "To Try for the Sun" and made it the opening track to their 1966 compilation The Real Donovan. The 45 was one of the records in John Lennon's jukebox.