Turquoise
CuA16(PO4)4(OH)85H2O
The Gods Wore Turquoise
The storyteller weaves his tale--
...from the base of an Olmec monument...
...as a scribe to a Mayan king...
...in a merchant's alley of Teotihuacan...
...from the steps of a Toltec temple made of turquoise...
...on the road north to Chaco...
...inside a Navajo hogan...
His words rise on smoke that stains ancient walls and, escaping the ghostly flames, travels across landscape and centuries carrying a brew of legends and myths. Feathered serpents, talking jaguars, murderous giants, and scores of hero twins who slayed monsters and returned from their quests with colored stones.
In those times, the gods wore turquoise. They carried turquoise scepters, wore masks inlaid with turquoise. Turquoise adorned heaven and graced temples.
In Zuni legend, Coyote picked up a turquoise stone, tossed it into the air, and so the sky was made. The Navajo say turquoise holds power to bring rain. Moving heaven and earth. Powerful elements associated with the blue stone.
As with most myths, there is truth at the heart, because the truth about how turquoise comes to be is perhaps the most fantastical of all.
Turquoise is a miracle of nature, an improbable product of long-shot ideal conditions:
- the right “mother rock”
- the right brew of minerals percolating in the rock
- the right amount of rainwater soaking into the host rock
- all at the right elevation
- and hundreds of thousands—if not millions—of years
History
The name turquoise is apparently related to the ancient Leventine traders (known as Turks). They brought the stone west into Europe from the eastern Mediterranean. Turquoise has been mined since before recorded time, in Turkey, Iran, and even China. Here in the United States, turquoise was found in the Southwest (Nevada, Arizona, New Mexico and Colorado), however most of the domestic mines are played out or it has become economically unfeasible to go after the turquoise, making high grade domestic turquoise rare. Small quantities are also found in Australia, Mexico, Chile and the Sinai Peninsula.
In our Southwest, Native Americans worked turquoise mines before the time of Columbus. Trade routes were established to these mines and ran through the Southwest, through Mexico, and south to the tip of South America.
The Making of the Miracle Blue Stone
Turquoise is a cuprous aluminum phosphate. The blue and green colors are determined by varying chemical combinations contained in the mineral. More copper, the greener the stone. More iron pyrite, the bluer the stone.
It is believed be formed from the water runoff carrying minerals collected and deposited into voids in rocks. The deposits hardened into turquoise. The lines in some turquoise stones are called “matrix” and is actually the mother rock hosting the turquoise. It can be made from several different elements, including chert, pyrite, quartz, cuperite, and manganese oxide. The highly prized spiderweb turquoise is made up of small nuggets naturally cemented together with rock or matrix. When cut, the aggregate mass of nuggets resembles a spider web.
Turquoise is a stone, not a color. The color of the stone actually has a huge spectrum, ranging from light green to dark green, light blue to dark blue to near purple. While variations in color can even happen within one mine, mines are also known for a prominent color and characteristics of their gem grades.
The value of turquoise depends on rarity and hardness. These two factors are the first to be considered by any expert grading. The hardness of turquoise is related to the grain size of the crystalline aggregate and has a range from 2 – 5 on the Moh scale. Gem quality turquoise would have the hardness of 5 to 6. The majority of turquoise has the consistency almost like that of blackboard chalk.
Rare, improbable, treasured...and yet found everywhere?
Demand for the blue stone has always been greater than supply. Industry sources estimate that only about 8% of all the turquoise mined is gem grade (a category of hardness). The other 90% is too porous to hold a color and too soft to grind or cut. It is, however, easy to dye and to permeate with plastics or resins. This is called stabilized turquoise.
Messing with Mother Nature
STABILIZING
Stabilized turquoise is lower grade stone (called chalk), that has been pressure-cooked with a polymer plastic composition. The process hardens the turquoise and brings out the blue color by filling in the pores.
Stabilized turquoise is generally accepted in heishi necklaces because of the turquoise waste generated by the grinding and polishing. Heishi making is extremely stressful on a stone and results in a lot of waste. That turquoise waste would be an expensive proposition with rare high-grade turquoise, sending the price of that turquoise necklace into the thousands. Stabilized turquoise set in silver, however, is viewed as less desirable (and unnecessary). Stabilized turquoise is the only “un-natural” stone allowed at Indian Market according to SWAIA standards. The New Mexico Arts and Sales Act prohibits the sale of stabilized turquoise without full disclosure.
You can sometimes detect stabilized turquoise by simply rubbing your thumb over the stone. The plastic will warm unnaturally from the heat of your skin. A sharp knife scraped judiciously across the top of the stone will gather white flakes of plastic. A reputable dealer informs his customers if a piece of jewelry includes stabilized turquoise. One of the hallmarks of Tanner Chaney and Native Gold is our guarantee about what we carry. We know the turquoise and the mines. In many cases, we have sold or provided the turquoise to the artist in the first place (and most often it is old American turquoise, high grade, and not easily obtainable in your usual Indian jewelry.
ENHANCED
Enhanced turquoise is turquoise exposed to high amounts of electricity in addition to crystal. The crystal fills the pores of the stone, delivering a hard and vibrant-colored stone...also one that is nearly impossible to detect as enhanced. The reason is that any “test” of the turquoise will reveal crystal in the makeup, which is a naturally-occurring material in natural turquoise.
BLOCK
This is the next step down and is similar to pressed wood in lumber. Block is a hardened “glue” of turquoise dust or chips. Telltale signs include an unnaturally uniform color with no variations. (Canny unscrupulous dealers have created block with matrix simulating the veins of mother rock. Still, the blue will have an opaque, consistent color.) Like stabilized, block is warmer when rubbed than natural. And block will turn colors since it is very absorbent.
FRACTURE SEALED
As difficult as enhanced to detect is fracture sealed. This is the process of “painting” a resin onto the soft matrix of natural turquoise, hardening the matrix so it doesn't crumble during polishing. An experienced eye can detect the unnatural sheen of the fracture seal.
IS IT AUTHENTIC?
Even for the collector, detecting what is high quality can be tricky. Stabilized can look like real. Imported Chinese turquoise can look like rare (and more expensive) domestic turquoise. Ask where the turquoise came from. Anyone of knowledge will name the mine, as that is most often how turquoise is referred to. Ask if the stone is natural, the name and tribe of the artist. Ask for a written certificate of authenticity. Even the unscrupulous dealer will hesitate, knowing that false answers can land him in jail with fines.
Price is another indicator. A $10 bracelet cannot possibly have high quality turquoise. A $50 strand of nuggets cannot possibly be natural.
At Tanner Chaney we are guardians of the authentic and the unique. We live by the principles that also guide the artists we work with. They have grown up with stories and prayers about turquoise, and in their pieces they work to honor the stone. We try our best to do the same for them.