[DOC] [TLE] Turquoise - Wikipedia [PAR] 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)84H 2O. It is 
rare and valuable in finer grades and has been prized as a gem and ornamental 
stone for thousands of years .... Iran also has turquoise mines in Semnan and 
Kerman province. [DOC] [TLE] 18thC Antique 4ct Persian Turquoise Ancient Roman Callais ... [PAR] ORIGIN: 18th Century Neyshabur, Iran. ... By 4,000 B.C., the turquoise mines in 
the Sinai had already been exhausted, and from that time ... most sought-after "
robin's egg blue" variety, from ancient Persian mines in modern-day Iran. .... As 
the color may pale when the stone has been worn for a long time, even high-
quality... [DOC] [TLE] Persian turquoise, jewel of the Orient - Visit Iran [PAR] It's sky-blue turquoise has always been a magnet for beauty seekers throughout 
history. ... Turquoise is a non-vitreous stone, which differs in shade from blue, 
green and ... Neyshabur turquoise mines, located 53 kilometers northwest of the 
city and ... and throughout the Caucasus dating back to the first to third century 
BCE. [DOC] [TLE] Chemistry - Ray Sahelian, M.D. [PAR] Chromium is a chemical element which has the symbol Cr. Chromium oxide ..... 
blue-green stone has been mined for centuries at Neyshabur in northern Iran. [DOC] [TLE] Sky Blue Stone - Arash Khazeni - Paperback - University of ... [PAR] From its remote point of origin in the city of Nishapur in eastern Iran, turquoise ... 
stone whose pale blue results from the presence of copper, turquoise has 
surfaced in ... been valued as a celestial object, and been traded across the 
world. A nineteenth-century Persian natural history compares the formation of 
turquoise to... [DOC] [TLE] Gemstone finds | Wondermondo [PAR] Aug 28, 2012 ... Some of these stones have color change effect - from blue in daylight to red in 
artificial light. ... One of the few finds of beautiful green gemstone - tsavorite. ... 
World's largest jade stone has been found here - it is 21 m long and 6 m high. ... 
Nishapur mines of turquoise (Neyshabur) - Iran, Razavi Khorasan. [DOC] [TLE] Turquoise Value, Price, and Jewelry Information [PAR] Over the past half-century, turquoise has withstood the vicissitudes of fashion 
trends. Today, the striking sky blue to blue-green stone is favored by well-known 
... Persia (Iran) introduced Medieval Europe to this stone. .... However, similar 
stones have been found in the US, particularly in the Sleeping Beauty Mine near 
Globe,... [DOC] [TLE] Encyclopedia of Gemstones - Turquoise ... - All Gem Stones [PAR] Color: The color of turquoise ranges from sky blue through various shades of 
green to ... the 4th millennium BC in one of the world's first important hard-rock 
mining operations. ... Turquoise is a sacred stone to many American Indian tribes 
and has been ... Deposits: Highly prized turquoise has come from Neyshabur, 
Iran. [DOC] [TLE] nishapur photos on Flickr | Flickr [PAR] Built in the 12th century (circa 1114), the building looks like a fortified rectangle 
from the ... Nishapur (Neyshabur), Iran ... Tomb of Omar Khayym in Neyshabur, 
Iran. ... Overall, Ottoman architecture has been described as a synthesis of the 
...... Turquoise is an opaque, blue-to-green mineral that is a hydrous phosphate of
... [DOC] [TLE] Turquoise - Mindat Mineralogy Messageboard [PAR] Jul 20, 2009 ... Turquoise has been used as a gem and ornamental stone since a very long time. 
.... They are early 20th century tungsten mines, working wolframite-bearing .... 
The northern, Turquoise Ridge, is separated from the southern, .... Fox turquoise 
is quite hard and runs from shades of green to an aqua blue color. [DOC] [TLE] about the stones [PAR] Turquoise has been mined since at least 6000 B.C. when it was mined by early 
Egyptians. ... In the thirteenth century, turquoise was believed to protect the 
wearer from falling,

Question: This blue-green stone has been mined for centuries at Neyshabur in northern Iran
Answer: turquoise