Grading Turquoise Color: What Color of Turquoise is Worth More?
Turquoise ranges in color from whitish blue to deep dark blue, and from deep dark green to a yellowish green. “The mineral turquoise actually parallels color itself and has many hues,” write Joe Dan Lowry and Joe P. Lowry of the Turquoise Museum. “This mineral has been mined in blues, greens, and whites.” Which of those colors is worth more is one of the oldest arguments in the trade. This guide gives you the expert answer, the scoring system this page has used for years to grade a stone’s color, and the colors the best-known mines produce, so you can judge the stone in any piece of turquoise jewelry before you buy it.
Blue or green: which turquoise color is worth more?
Neither, by default. The U.S. Indian Arts and Crafts Board, in a consumer guide written with the Turquoise Museum, puts it plainly: “Natural blue and green turquoise stones are the most sought after and have many color variations. However, neither of these two colors is more valuable than the other.”
What moves the value is how deep and clear the color is. The same guide: “The higher grade turquoise has greater clarity and deeper color.” The Lowrys add the working rule: “The darkest colors are the rarest to find and therefore have a greater value than lighter colors. It is important to compare blue colors of turquoise to other blues and green colors of turquoise to other green colors.” Blue is the more popular color, they note, “but there are several famous mines that produce green turquoise and are very collectible in their own right.”
So compare like with like. A deep, clean green can outgrade a pale, chalky blue, and the reverse is just as true.
What gives turquoise its color
The color is chemistry. Joseph E. Pogue, in his 1915 study for the National Academy of Sciences, describes turquoise as “a phosphate of aluminum carrying small quantities of copper and iron, to which its color is due.” The usual rule is that copper makes blue and iron makes green. Paula Baxter’s Encyclopedia of Native American Jewelry states it directly: “Its blue colors are caused by copper concentrations, and its green tones by iron.” Pogue was more careful. That explanation, he wrote, “can not be regarded as thoroughly established.” Treat it as a good rule of thumb, not a law.
Turquoise also belongs to a family of closely related minerals, and one of them is often taken for a kind of turquoise. The Lowrys: “Turquoise is the aluminum-rich member of the series, with faustite being zinc-rich and chalcosiderite being the iron-rich members of the series.” Faustite is a separate mineral, not a rarer grade of turquoise. We say so plainly because an earlier version of this page had it wrong.
Treatment changes color too. The IACB defines stabilized turquoise as turquoise “combined with colorless resins (plastics) under a vacuum or pressure to harden the stone and darken the color,” and dyed turquoise as stone to which “a pigment is added to deepen the stone’s color or create a ‘matrix’ design within a treated stone.” A deep color is only evidence of grade on a natural stone. To check what you are looking at, see how to tell if turquoise is real.
How Color Influences The Value of Turquoise
There is no single grading standard for turquoise color, and the reason is historical. The Lowrys: “The most well known tradition of grading turquoise is the Persian system, which defines the best grade as a stone with perfect clarity and the deepest blue color. The American system defines the best grade as a stone that is from one of the most famous and rare mines that has a good blue color and a spiderweb matrix.” That is why one dealer’s top color is another’s ordinary stone: “just as some turquoise dealers might consider one turquoise mine or color high grade, others might classify it as common or even low grade.”
It is generally accepted that a rich, even color is worth more. The Turquoise Quality Index (TQI) is the 100-point scoring guide this site uses to put a stone on a scale, and color is one of its eight scores. It is not an industry or laboratory standard, because the trade doesn’t have one. Its job is to make you look at the same things every time. Color is scored from 1 to 10 on two things: intensity and transition. Imitation (synthetic) stones always score 1. Dyed stones never score higher than 2. Natural stones are examined more closely, and their score is 1 + intensity + transition, with the total capped at 10.
Imitation = 1
Dyed = 2
Natural = 1 + Intensity + Transition (maximum 10)
| Color (1–10) | Imitation | Dyed | Dull, cloudy, harsh transitions | Limited color, imperfect transitions | Dark color, smooth transitions | Rich color, smooth transitions |
|---|---|---|---|---|---|---|
| Points | 1 | 2 | 3–5 | 6–7 | 8–9 | 10 |
Grading Turquoise Color Intensity
Intensity is how rich and deep the color is, from white through pale, light and medium to rich. As a rule, the richer the color, the rarer and more valuable the stone. When a stone shows more than one color, always score the lower-scoring color.
White stones: +3
Pale stones: +1
Light colors: +2
Medium colors: +3 to +4
Rich colors: +5
Dark colors: +4
Two notes on those bands. First, the TQI scores a rich, saturated color one point above a very dark one. Second, white needs care. The IACB: “The most common turquoise color is white. White turquoise, referred to as ‘chalk,’ is generally too soft to cut or polish and is not typically graded as a gemstone.” A white stone hard enough to cut and polish is the exception, and that is what the +3 rewards. Make sure it is turquoise at all. “Magnesite, dolomite, howlite, and calcite are not turquoise,” the Lowrys write, “but each has been marketed in the turquoise industry for their unusual combinations of white colors and matrixes.” If a white stone is sold to you as turquoise, ask for the mineral in writing.
This scale shows example colors, the lightest on the left and the darkest on the right.
Grading Turquoise Color Consistency
The second color score is consistency: how evenly the color holds, and how smoothly one shade moves into the next. This scores changes in the turquoise’s own color, not the edge between turquoise and its matrix, which is a different material. Color transitions happen for many reasons. The chemistry of the host rock can change how the color forms, and stabilization can leave harsh marks on a stone. Sharp, harsh transitions are worth less than smooth, even ones. When a stone has several transitions, score the worst one.
Obviously harsh transitions: +1
Sharp color, inconsistent color transitions: +2
Minor transition imperfections: +3
Smooth color transitions: +4
Perfectly uniform color: +5
This scale shows example transitions of color, the harshest on the left and the most desirable on the right.
Examples of Grading Turquoise Color
This stone shows a smooth transition between a classic sky blue and a richer, darker green. It is natural, so it is scored 1 + intensity + transition. Score the lower-scoring color: the blue is less rich than the green, so the blue is the measuring color. It is a medium blue, earning +3. The move from green to blue is very smooth, earning +4. The total color score is 1 + 3 + 4 = 8.
This is a natural rich green stone with a harsh transition to a lighter green near the top of the cabochon. Score the lower-scoring color: the lighter green is still fairly rich, earning +4. The harsh circular mark at the top right costs it on transition, earning +1. The total color score is 1 + 4 + 1 = 6.
This is a pale blue stone from the Burnham mine. Its even color presents nicely, but it is not a rare or rich color, so intensity scores +1 for pale. It has no real transition problems, earning +4. The total color score is 1 + 1 + 4 = 6.
This is a naturally brilliant blue stone. The color is not rare, but it scores highly for intensity, earning +4. There are some noticeable transition imperfections, though not enough to distract, earning +3. The total color score is 1 + 4 + 3 = 8.
Color is one of eight TQI scores, alongside hardness, treatment, composition, cut, availability, matrix and size. The full index is in the Turquoise Quality Index guide linked above.
Turquoise colors by mine
Where a stone was mined shapes its color, and it shapes its value even more. The Lowrys: “The most influential rarity of a turquoise’s value is where a specific turquoise was mined.” The IACB names the mines it holds in highest regard: “Many mines, such as Lone Mountain, #8, Lander Blue, and Bisbee mines, are highly regarded for the color, matrix, and history of the turquoise they contain.” Here is what the reference books record for the names you will see most often. For every mine on one map, see our turquoise mines field guide.
Kingman and Sleeping Beauty, Arizona
These two set the color most people picture. “The production amounts of Kingman’s blue colors along with Sleeping Beauty’s similar hues have made this color of turquoise the most common ‘look’ of any American turquoise” (Lowry). Sleeping Beauty runs “from a chalky white to a sky blue with a clarity that can rival similar turquoise that is famous from the countries of Iran and Chile.” Kingman, in Nancy Schiffer’s words, “has produced light to dark colored turquoise and a great deal that is treated.” Sleeping Beauty is closed, and in Chambless and Ryan’s account Kingman holds Arizona’s one remaining turquoise concession. Compare the two side by side in Kingman vs Sleeping Beauty turquoise.
Bisbee, Arizona
Bisbee is known for depth of color and a matrix you can recognize. Oscar T. Branson, writing in 1975: “The best grades are the deep, intense blue, with slight transparency and a dark reddish-black mottling or veining.” That matrix sometimes forms “whisps or veils throughout the stone, often called ‘Smokey Bisbee.’” The Lowrys describe the same stone as “famous for its smoky- or lavender-colored matrix.” Bisbee produced greens too: Branson records “many shades from light to dark blue, and light to very attractive dark green.” The mine is closed.
Morenci, Arizona
“The Morenci Mine in Arizona is famous for a nice blue color and pyrites in its matrix formation” (Lowry). Schiffer describes “light to dark blue stones with a light tan matrix.” Morenci is closed as well. Chambless and Ryan: “The mines at Bisbee, Morenci, Castle Dome, and Sleeping Beauty are all closed, with little prospect of any turquoise ever again coming from those areas.”
Royston, Nevada
Royston is a district, not one mine. Its deposits, the Lowrys write, “have been marketed using names such as Oscar Wehrend, Royal Blue, Bunker Hill, and Royston. The Royal Blue site is the largest.” Because the stone from these sites looks alike, “the turquoise from this area is generally marketed using the name Royston.” Schiffer describes the Royal Blue mine’s stone as “dark green and blue color with brown matrix.”
Carico Lake, Nevada
Carico Lake produced both turquoise and a green look-alike. The Lowrys: “This area has produced many colors of turquoise as well as the apple green mineral faustite.” That green is faustite, the zinc-rich cousin of turquoise described above, so ask which mineral you are buying. Our documented turquoise stone study photographs real stones mine by mine, and Carico Lake is one of the mines you can see there now.
Blue Gem, Lander Blue and Lone Mountain, Nevada
Blue Gem is the clearest case of blue and green in one stone. Schiffer: “Characteristically, Blue Gem turquoise has deep blue to deep green coloring in the same stone.” Lander Blue “is best known for its deep-to-light blue spider web turquoise with black matrix,” and part of its fame is scarcity: the Lowrys record its “limited production (estimated at 108 pounds rough).” Lone Mountain, Schiffer writes, “produces good to high quality turquoise of light to medium color.”
A mine name adds value only if it is true. The Lowrys warn that “Mexican turquoise has been misrepresented and sold as Kingman turquoise since before the 1970s,” and they give the remedy: “If the consumer wants to buy a turquoise from a Classic Mine, then he or she needs to get a written guarantee of the mine source from the miner and salesperson.”
Can turquoise color change?
Some can. The Lowrys: “Many soft, medium, and lower grades of turquoise that are shaped into beads or cabochons are processed in oil or wax-based polishes. These turquoises are susceptible to a slow loss or change of color.” Dye can fade: “When a color dye is added to this process, the color is susceptible to breaking down over time due to direct sunlight or changing temperatures.” And soft spots in a stone can “oxidize to a yellow color over a period of time.” For the full story, see does turquoise change color?
Choosing a color
Grading tells you what a color is worth. It doesn’t tell you what to wear. The Lowrys end on the same point: “Many times the consumer just buys what he or she likes and can afford.” Use the scores to know what you are paying for, then choose the stone you like. When you are ready, browse our turquoise collection, and for how color and matrix read together in a finished piece, see the turquoise look: color and pattern.
Frequently Asked Questions
Is blue turquoise worth more than green?
Not automatically. The Indian Arts and Crafts Board says blue and green are both “the most sought after” and that “neither of these two colors is more valuable than the other” (IACB brochure, p. 2). Depth matters more than hue: “The darkest colors are the rarest to find and therefore have a greater value than lighter colors” (Lowry, Turquoise, p. 184).
What gives turquoise its color?
Copper and iron. Pogue describes turquoise as “a phosphate of aluminum carrying small quantities of copper and iron, to which its color is due” (The Turquois, 1915, p. 7). Baxter gives the usual rule: “Its blue colors are caused by copper concentrations, and its green tones by iron” (Baxter, Encyclopedia of Native American Jewelry, p. 182), though Pogue warned it could not yet “be regarded as thoroughly established” (p. 23).
Is white turquoise rare?
No. “The most common turquoise color is white,” and most of it is chalk that is “generally too soft to cut or polish and is not typically graded as a gemstone” (IACB brochure, p. 2). Some white stones sold alongside turquoise are other minerals: “Magnesite, dolomite, howlite, and calcite are not turquoise” (Lowry, p. 119).
Is faustite turquoise?
No, it is a related mineral. “Turquoise is the aluminum-rich member of the series, with faustite being zinc-rich and chalcosiderite being the iron-rich members of the series” (Lowry, p. 114). The Lowrys describe Carico Lake, Nevada, as producing “the apple green mineral faustite” (p. 234).
Which turquoise mine is known for the darkest blue?
Bisbee is the classic answer. Branson describes its best grades as “the deep, intense blue, with slight transparency and a dark reddish-black mottling or veining” (Turquoise: The Gem of the Centuries, 1975, p. 32). The mine is closed (Chambless & Ryan, Turquoise in America, p. 187).
From the Library: Pogue, The Turquois (1915)
1915 primary source. Anything described as current here describes 1915, not today.
As of 1915, Pogue described the trade's preference:
“The most approved tint, from our viewpoint, is a pure blue, called in the trade sky-blue or robin’s-egg blue.”
— Pogue (1915), p. 23
Pogue (1915) continued:
“Comparatively few stones, however, are entirely free from a green element, and with increasing greenness the value in general lessens.”
— Pogue (1915), p. 23
Pogue (1915) also noted how rare top color was:
“The large proportion of all turquois mined is utterly worthless, so inferior and unattractive is its color. Upon the rarity of the finest-colored specimens is dependent to large degree the value of this mineral as a gem.”
— Pogue (1915), p. 23
Writing about 1300, the Arabian mineralogist Muhammed Ibn Mansur ranked color this way, in Pogue's 1915 translation:
“The best color is dark-green; the next best, whitish-milky;then skyblue.”
— Pogue (1915), p. 72
Pogue (1915) also noted a different ranking among Arab authorities:
“On the authority of Ibn-el-Beithar and al-Beruni, stones of fine blue color took foremost rank among the Arabs.”
— Pogue (1915), p. 74
On the old Tibetan scale, Pogue (1915) quoted Berthold Laufer:
“Deep-blue, lustrous stones without flaw took foremost rank; white and red strips or layers were not considered a blemish, but rather a special beauty; the lighter the blue, and the more approaching a gray and green, the more it sank in estimation”
— Pogue (1915), p. 77
And on Southwestern buyers in his own day, Pogue wrote in 1915:
“The Indian is usually a rather keen judge of quality, although he does not so strongly favor the blue color, to the exclusion of the green, as does the white man.”
— Pogue (1915), p. 101
At the Nishapur mines, Pogue (1915) reported, the top class was:
“All stones of pleasing, permanent color and favorable shape are called Angushtari, meaning ring stones, and are sold by the piece.”
— Pogue (1915), p. 38
On colour, Pogue (1915) wrote:
“The most valued color is deep sky-blue; the slightest imperfection, or an almost inappreciable tinge of green, decreases the value considerably. A deep indigo-blue, called “talkh,” or bitter, also lessens the value.”
— Pogue (1915), p. 38
Pogue (1915) added a quality that colour alone cannot supply:
“A good stone, in short, must possess an indefinable property called the “zat,” which is something like the “water” of a diamond or the luster of a pearl; a fine-colored turquois without the “zat” is not of much worth.”
— Pogue (1915), p. 38
At the bottom of the Persian scale, Pogue (1915) explained,
“Since then any pale-colored, greenish, or spotted turquois is called Arabi.”
— Pogue (1915), p. 39
From the Library: Khazeni, Sky Blue Stone (2014)
2014 primary source. Anything described as current here describes 2014, not today.
These grades are those of historical Persian books of stones, reported by Khazeni; they are history, not a modern grading standard.
Khazeni (2014) on how the Persian trade named the colour:
“Turquoise, stone and color, was called firuza in Persian and fayruz in Arabic, but its color (rang) was often referred to as asuman gun (sky colored) or rang-i asumani (the color of the sky).”
— Khazeni (2014), p. 35 [2]
The Javahirnama of Ibn Mansur, as Khazeni (2014) summarises it, gave the top colour to a single Nishapur mine:
“The ultimate and maximum color (bi qayat rangin) belonged to the luminous turquoise of the old Abu Ishaqi mine.”
— Khazeni (2014), p. 36 [2]
Khazeni (2014) on colour and price in the Persian trade:
“Color determined the value of turquoise on the market and was seen as the source of the stone’s many virtues.”
— Khazeni (2014), p. 36 [2]
From the Library: Lowry, Turquoise Unearthed: An Illustrated Guide (2002)
2002 primary source. Anything described as current here describes 2002, not today.
Lowry (2002) on the colour question:
“Perhaps the most common misconception is that blue turquoise is more valuable than green.”
— Lowry (2002), p. 34 [3]
Lowry (2002) gave the counter-example:
“A blue stone with a spiderweb matrix is worth more than a green stone, but a green stone from the Blue Gem mine is worth more than a high grade blue Sleeping Beauty stone.”
— Lowry (2002), p. 34 [3]
Lowry (2002) summed it up:
“Mine and matrix matter more than color.”
— Lowry (2002), p. 34 [3]
According to Lowry (2002, p. 34), Middle Eastern, European and Asian collectors favored stones of exceptional clarity, uniformly colored and without impurities, commonly called "robin's egg"; to get that look, the host rock may be sawed away or the stone shaped to hide its impurities. [3]
From the Library: Welch, Indian Jewelry (1973)
1973 primary source. Anything described as current here describes 1973, not today.
As of 1973, Welch reported a colour preference and the names that went with it:
“The Navajos and Zunis prefer stones which have a clear, deep robin's egg blue color. They call this "male turquoise."”
— Welch (1973), p. 52 [4]
According to Welch (1973, p. 52), stones with a greenish hue, which she described as less rare, were called "female" turquoise. [4]
Welch (1973, p. 53) also wrote that the best deep blue stones kept their colour, while lighter blue and greenish stones were softer and eventually turned dull and greener. [4]
Welch (1973, p. 67) listed the colours turquoise was then found in, from sky blue and light greenish blue to almost white, dark blue, dark green, reddish brown and even violet, and reported that the proprietor of one mine claimed to have seen more than 200 different shades. [4]
From the Library: Lund, Indian Jewelry: Fact and Fantasy (1976)
1976 primary source. Anything described as current here describes 1976, not today.
According to Lund (1976, p. 33), the first turquoise stones set in Navajo silver were, on the whole, green and flat on top; blue stones cut as rounded cabochons gained popularity only some years later. [5]
Field Notes by Mateo James
I notice Pogue's 1915 ranking and the IACB guidance on this page disagree: Pogue put pure sky-blue first and said value generally fell as green increased, while the IACB says neither color is worth more than the other. Chambless & Ryan record that the desired color in the early American turquoise rush was non-matrix sky blue, which matches Pogue's time. I tend to side with Chambless & Ryan, and they describe that preference as belonging to that era.
I notice the two readings of Ibn Mansur disagree on his top colour. In Pogue's 1915 translation he ranks dark green first, then whitish-milky, then sky blue, while Khazeni (2014), reading the Persian Javahirnama, has him praising the unfading sky blue of the old Nishapur mines and giving the utmost colour to the Abu Ishaqi stone.
I want to flag a difference on this page. The guide follows the Indian Arts and Crafts Board, which says neither blue nor green is worth more by default, while Welch (1973, pp. 52-53) reported a clear preference among Navajo and Zuni buyers for deep robin's egg blue and wrote that lighter and greenish stones were softer and faded. Both views are here so you can weigh them yourself.
Sources
- U.S. Department of the Interior, Indian Arts and Crafts Board, with Joe Dan Lowry (Turquoise Museum). Indian Arts and Crafts Act turquoise consumer brochure (GPO gpo58769). n.d., pp. 1–2.
- Joe Dan Lowry & Joe P. Lowry. Turquoise: The World Story of a Fascinating Gemstone. 2010, pp. 17, 114, 119, 179–180, 184, 224, 226, 231, 234.
- Paula A. Baxter with Allison Bird-Romero. Encyclopedia of Native American Jewelry. 2000, p. 182.
- Oscar T. Branson. Turquoise: The Gem of the Centuries. 1975, p. 32.
- Philip Chambless & Mike Ryan II. Turquoise in America: The Great American Turquoise Rush 1890–1910, Part 1. Callais Press, 2021, p. 187.
- Joseph E. Pogue. The Turquois (Memoirs of the National Academy of Sciences, vol. XII). 1915, pp. 7, 23.
- Nancy N. Schiffer. Turquoise Jewelry, revised 4th ed. 2008, pp. 7, 11–12.
- Pogue, Joseph E. The Turquois: A Study of Its History, Mineralogy, Geology, Ethnology, Archaeology, Mythology, Folklore, and Technology. Memoirs of the National Academy of Sciences, Vol. XII, Part II, Third Memoir. Washington, 1915. Public domain. Cited by printed page. Statements describe conditions as of 1915.
- Khazeni, Arash. Sky Blue Stone: The Turquoise Trade in World History. The California World History Library 20. Berkeley: University of California Press, 2014. Cited by printed page. Statements describe conditions as of 2014.
- Lowry, Joe Dan, and Joe P. Lowry. Turquoise Unearthed: An Illustrated Guide. Photography by Mark Nohl. Tucson, AZ: Rio Nuevo Publishers, 2002. Cited by printed page. Statements describe conditions as of 2002.
- Welch, Frankie. Indian Jewelry: How To Wear, Buy and Treasure America's First Fashion Pieces. McLean, VA: EPM Publications, Inc., 1973. Cited by printed page. Statements describe conditions as of 1973.
- Lund, Marsha Mayer. Indian Jewelry: Fact and Fantasy. Boulder, CO: Paladin Press, 1976. Cited by printed page. Statements describe conditions as of 1976.
