-Identifying the value of varios grades and matrix inclusions-
What is the value of your turquoise stone? Finding out how much a turquoise stone is worth is a common concern among turquoise collectors . The price of turquoise stones normally range from $1 to $10 per carat
A unit of measurement used to measure turquoise and other precious gems and metals = carat weight
5 Carats = 1 Gram">carat but can range from $0.05 to $1000 per carat depending on the quality. The difference between quality turquoise and cheaper stones can be a little confusing. There are many factors in play that determine a stone’s price, some are subjective and others tend to change over time. The weight of the stone and the Turquoise Quality Index can help us determine how much a stone is really worth.
Turquoise Price = Weight (Carat) X Turquoise Quality Price/Carat Index (TQI)
Turquoise is weighed in carats, where 5 carats equals 1 gram. The heavier the stone, the more valuable it is. It is common to see turquoise priced per carat when it is for sale. So the first step is to weigh the stone, and then figure out what the price is per carat. This price can range from $0.05 to $500 per carat, depending on the stone.
Turquoise Quality Index
The Turquoise Quality Index (TQI) is a measurement of the quality of the turquoise stone. The TQI is a number on a scale between 8 and 100. The higher the TQI number, the better quality the turquoise, the higher the grade and the more valuable the stone. High numbers are rare; less that 1% of turquoise on the market score a 90 or better.
Physical structure makes up 55 points (100%) : Hardness (20), Enhancement (20), Composition (10), and Cut (5).
|55 points (total)||20||20||10||5|
|GRADED 90-100||AAAA||Superior||less than 1% available world wide||$50-$1000/carat|
|GRADED 80-89||AAA||HIGH||2-3% available WW||$30-$50/carat|
|65-79||A - AA||Medium||10%||$1.00-$2.50/carat|
The green turquoise cabochon, from an American mine, might become part of a designer’s unique jewelry piece.
The even blue color of the cabochon on the right would be called Persian blue in the trade.
Excellent-quality turquoise is sought after around the world by designers of unusual jewelry pieces.
Typically, whether a fashioned turquoise meets the ideal or departs from it, it’s judged on three basic qualities—its color, its texture, and the presence or absence of matrix.
Turquoise is a beautiful, semi-hard, opaque, triclinic cryptocrystalline stony mineral found in shades of red brown yellow green and the most highly coveted (PERSIAN BLUE ) or American robins egg blue which can range from very opaque to very intense blue due to the rich (Aluminium) aluminum and copper in the volcanic Oregon river-soil . Chemically, it is a hydrated aluminum copper iron and phosphates which results in a variety of complex and unpredictable formations.
A reddish brown metal that is used for jewelry making.">copper phosphate. In an arid environment, turquoise forms inside the earth within host rocks (such as limestone and sandstone) under and high temperature and pressure, making it as hard as glass
A hard transparent substance made by melting and rapidly cool sand with other ingredients.">glass. The combination of different elements in the host rock
Rock where a precious metal or other material forms. With turquoise the host rock material becomes the matrix. ">host rock material can change the appearance and structural integrity. Some turquoise is not formed completely and needs the aid of enhancing agents to make it usable in jewelry. The resulting stone’s physical properties are key indicators that help determine the value of the stone.
The most-prized turquoise color is an even, intense, medium blue. But some consumers prefer a greenish blue, and some contemporary designers actively seek avocado and lime green turquoise.
The turquoise in the broach and graduated bead strands is from Arizona’s Sleeping
Beauty Mine. Its smooth, even color is made from impregnating the natural stone with binders and intensely heating the stone to bake it into a glass like surface which is for the lack of a better term ( junk turquoise) the color that is achieved represents the appearance prized by most collectors but is often unobtainable naturally. our collection of available natural (from the ground ) OREGON turquoise is of extreme clarity and quality of natural robins egg blue and ranges from gorgeous light opaque BLUE - to the darkest blues, greens or blacks depending on the location of extraction and specific mineralogical inclusions during formation here in the rivers and waterways of Washington and Oregon's many uncharted natural mountain trail-systems. Bellow is an example of the extreme quality and clarity of our available OREGON river turquoise which is of a visiably unpresidented coloration of absolute breathtaking beuty and provides an unmachably gorgoiuse accent to any fine jeweler works of masterery in such settings as wood silver and gold hich helps to frame the one of a kind pieces. each indevidule turquoise is unique and different in its inclusions (just like a snowflake / fingerprint)
ABOVE (HIGH quality AAA grade -hand polished- NATURAL Oregon turquoise) the quality rivals any well known turquoise samples available on the open market. Comparably colored to the well known (SLEEPING BEAUTY) Persian BLUE turquoise usually in Arizona .
Turquoise can be semi-translucent to opaque, with a color that usually ranges from light to medium blue or greenish blue. It’s often mottled, and sometimes has dark splotches. It might also have veins of matrix running through it which can highly increase the value and overall desirability of any piece (matrix is a remnant of its surrounding rock or inclusions of base minerals).
Turquoise Stone Composition
The composition of turquoise measures the materials that make up the stone. Turquoise by nature is a very chalky stone and the degree of chalkiness is a good quality indicator. Generally the more grainy or powdery the stone is the lower the quality. Turquoise is always formed on another material. This material is called the host rock. The host rock is a completely different material and has its own qualities that can either increase or decrease the worth of the stone. Plastic is not really turquoise (1), reconstituted turquoise has been mixed with plastics and receives a low score of (2-3). Lesser host rocks can be unstable. Turquoise can sometimes be not formed completely, causing the stone to be structurally weak which makes the stone less valuable these stones require some stabilization to even be usable(4-5). A stone that has a solid stable matrix or has been stabilized would receive (6-7) points. If a stone is professionally stabilized or natural with a completely solid turquoise (no matrix present) or has a solid matrix (8-9) points.
This is a widely disputed subject, because in some countries it is highly desired to have a pure turquoise stone. The TQI scale promotes rarity, and other elements in turquoise can be more rare in nature. Turquoise can contain other rare elements (such as pyrite
A golden colored material consisting of crystalline iron disulfide flakes found in a stones matrix.">pyrite which gives depth and metallic quality to the appearance of the stone without compromising structural integrity (10).
The time and energy needed to process raw stones to make them presentable adds a small value. Raw turquoise stones, also known as rough stones, are stones that have been pulled directly from the earth in its most natural state. In an unprocessed state it can be very hard to judge the true value of the stone. It must first be processed so that the stone can be displayed at its finest. Raw stones have now added value (1). Stones can be rolled and polished, machines can help to create standard size cabochon. A cut and polished gemstone usually in a round or oval shape and flat on one side.">cabochons
for mass production jewelry making (2). Stones or can be made into cabochons by machine (3) or can behand cut and shaped cabs (4). Finally, stones can be sculpted by an artist (5).
|Cut||raw||rolled or cut||standard machine cab||hand shaped cab||hand sculpted design|
|1 to 5||1||2||3||4||5|
The less available the stone, the more valuable it is. For example, turquoise can be plastic and easily produced. Mass production of plastic is not valuable and receives a (1) on the TQI scale. Reconstituted turquoise is made from easily available chalk and receives (3) points. The most common indicator on an individual stone’s availability is the turquoise mine. Different mines produce varying quantities of turquoise; within one mine we can find different grades, colors and patterns. This causes this scale to fluctuate from year to year based on the mine’s production and distribution of the turquoise. Common mines such as the large production Chinese mines (6) and the Kingman. The name of a Turquoise mine in Northwest Arizona. Known for its wide variety of turquoise. ">Kingman mine (12) produce a lot of turquoise. Some smaller or uncommon mines are well known, but don’t produce as much. Good examples here would be DRY CREEK/ BEAR CREEK & B.R.C.M.
The name of a turquoise mine in central Nevada known for its quality off white turquoise stones">Dry Creek and Easter Blue
(SPECKLED EGG PATTERN) inclusions of spots and small lines on a blue natural turquoise can be HIGHLY values and RARE...
Turquoise mined from spots located in the Royston District in south central Nevada known for its blue speckled turquoise. ">Easter Blue These mines get (13-17) points. Tiny rare mines such as Lander Blue in Nevada, is said to only have produced a few handfuls of nuggets. This makes the turquoise very rare and the value of the stones increase dramatically. These types of mines are called “hat mines” because the amount of turquoise that comes from the mine can fit in a miner’s hat (18-19). Also, rare specimens from any of the mines fall into this category as well receiving (18-19). Lastly, turquoise has been known to develop in other ways such as on fossilized organic remains. Fossil turquoise and petrified wood
Fossilized remains of wood that has turned into stone.">petrified wood turquoise are good examples. This is extremely rare and receives a score of (20). = petrified (TURQUOISE) wood - which occurs when petrification happens near the early bed of newly forming infant turquoise which then uses the surrounding woods as a host stone
|Availability||synthetic||chalk or reconstituted||common mine||uncommon mine||rare hat mine or rare specimens||extremely rare|
|1 to 20||1||2-5||6-12||13-17||18-19||20|
Turquoise color is one of the more controversial indications of stone value. The ancient Persians would say that the blue color of a robins egg is the most valuable;
some modern collectors say the green colors are more valuable though the Persian blue is UN-arguably the rarest and most beautiful by far.
Regardless of the color, clarity is an important indicator of stone value. Rarity, consistency, and contrast of the color are more important factors because color preference are very subjective. This means the hue of the color is not being judged as much as its purity and clear expression. Synthetic turquoise is always a (1) as the color can be controlled, this includes the synthetic color of reconstituted turquoise. Artificially dyed stones received a (2) depending on the consistency of color. Natural stones of very cloudy, dull or rubbery colors with harsh transitions between color shades and matrix get receive (3-5) points. It needs to be noted that cloudy is not the same as white or lighter shades of blue but more a paling or graininess of the natural color. Natural stones that feel limited in the true color expression and may have a grainy clarity (6-7). Stones with consistently rich color, sharp clarity but may have a slight inconsistency (8-9). Finally rare natural colors with consistently sharp clarity receive (20) points
|Color||synthetic||artificially dyed||dull, cloudy/harsh transitions||limited expression of color, imperfections in color transitions||Rich color, smooth color transitions||rare color, smooth color transitions|
|1 to 20||1||2||3-5||6-7||8-9||10|
Matrix PatternPattern is also a controversial indication of stone value. In Persia, a pure turquoise stone free from any matrix is the most valuable. Contradicting American collectors feel that the variation of spiderwebA pattern of matrix that looks like a spider web. ">spiderweb matrix patterns is the most valuable . Clarity simply means to be clear or have good contrast. The less dull, cloudy and blurry a stone is, the more valuable it becomes. Rarity is the focus of the TQI scale. Synthetic turquoise is always a (1). Engineered patterns of reconstituted turquoise (2-3) depending on the complexity. Sparse matrix with no apparent pattern (4-5) points. Consistent matrix with little patterning or pre rare patterning (6-7). Rare patterns such as spider web, face stone, calico or pure matrix free turquoise receive (8-9). Finally, natural stones with over exaggerated rare patterns receive (10) points. It should be noted that pure matrix free turquoise cannot be over exaggerated.
|Matrix||synthetic||artificially dyed||no pattern, Cloudy clarity||common pattern, grainy clarity||rare patterns, flawless clarity||rare patterns, flawless clarity|
|1 to 20||1||2||3-5||6-7||8-9||10|
The material known as spiderweb turquoise contains fine seams of matrix that form attractive web-like patterns.
These free-form turquoise cabochons show a typical matrix pattern.
The most valuable turquoise is an even medium blue, with no matrix and the ability to take a good polish.
No two turquoise stones are alike. The fragments and impurities of the host stone that are not transformed into turquoise create a MATRIX. the parts of the (host rock) which can contain a pelethera of unpredictable minerals. A complex matrix can have a variety of lovely unique colors and patterns.
Synthetic PLASTICS / Synthetics combined from polymers and binders such as colored plastics. This specific grade also includes fake or fabricated turquoise that is white originally and has been dyed blue and machine molded. this means they are not natural (FROM THE GROUND) and can be mass-produced. JEWELRY AND ROUGHS sold at shops or in fairs/merchant shops are fake/enhanced and have little value.
On the other hand, a calcium rich sea-shell (fossilized) turquoise / fossilized copper oxidized mineral bed seashell turquoise can form into a solid blue-bluegreen turquoise if it happened to fossilize near a copper vein in the surrounding area. While this is extremely rare, this can occur in just the right conditions. The rarities of this origin of turquoise, along with other rare quality indicators, bring tremendous value to our favorite blue stone.
Rarity consists of 45 points: Origin (20), Color Pattern (20) and Contiguous Size (5).
|45 points (total)||20||10||10||5|
Turquoise is most often fashioned as a cabochon. The smoothly rounded dome shape sets off turquoise’s color, texture, and any matrix beautifully. In addition, manufacturers and artisans fashion turquoise rough into round or oblong beads for strand necklaces, and into small, flat pieces that are popular in jewelry inlays. Some top-color blue turquoise is engraved with Persian or Arabic inscriptions, inlaid with gold. Other rough material might be tumbled into “nuggets".
This stylish and unusual “Pegged Nugget” bracelet contains about 100 flat turquoise nuggets that are attached with flat silver pegs. -
Gift of Robert Lee Morris
This intarsia box created by Nicolai Medvedev includes flat pieces of turquoise as part of its inlaid design. - © GIA & Tino Hammid, gift of Carol and Fred Seeman
Size That Matters
This is a simple quality that is easy to measure and understand. Even though a very large piece of turquoise might weigh the same as several small pieces, it is usually worth slightly more per carat. This is because it is harder to find large contiguous pieces in nature than small pieces. Again, it is a very small factor and does not usually cause a dramatic change in price. A piece smaller that ¼” at its widest point receives (1) points; between ¼” and 1” (2) points, 1” to 2” (3), 2” to 4” (4). Finally, any stone longer than 4” at its widest measurable point (5).
|Contiguous size||smaller than 1/4″||1/4″ to 1″||1″ to 2″||2″ to 4″||4″ +|
|1 to 5||1||2||3||4||5|
(on the left) The vintage silver setting is a salvaged antique and the stone is a natural raw OREGON turquoise (hand polished)
(MIDDLE) The larger blue piece may be used as the center most part of a massive priceless one of a kind belt buckle...
(on the right) whereas the dark green beauty may be used as a part of a bracelet or pendant for a unique, rare and highly valued necklace...
(ABOVE) this highly unique and amazing natural green sample is nearly 200 Carats by weight and is between 5-6 mohs hardness (unpolished)
Measuring Stone Hardness
Hardness is a measurable quality that indicates how easy a material can be scratched. Naturally the harder the turquoise the more valuable it is. Hardness is measured on a scientific scale called the “Mohs Scale” According to the scale, Turquoise has a similar hardness to glass. A Mohs scratch test can be preformed to determine the exact hardness of a material; however doing so would damage the stone that you are trying to measure. For the purpose determining TQI we don’t recommend damaging your precious stone! Simply use deductive reasoning. If the stone is solid then it is probably in the Mols pre determined turquoise range between 3 and 6. For stones that are obviously lower quality use the chart below(1-5). Brittle natural stones that are usually cloudy or stone that have been poorly stabilization
Also known as bonding, stabilization is the binding of turquoise or other natural substances with plastic or glass to increase the durability.">stabilized receive (10) Stones that have been professionally stabilized are not allowed to receive more than (15) points even if they have a high hardness. Natural stones that seem dull and feel chalky are most likely under 5 on the hardness scale and receive (10). Rare high hardness natural stones may receive (20) points for hardness. If you cannot tell, then give it a (15).
|Hardness||plastic||chalk||reconstituted||Below 5 on MOHS scale||pro stabilization 5+ on MOHS scale||high natural hardness MOHS scale 5+|
|1 to 20||1||3||5||10||15||20|
Turquoise is available in a wide range of sizes. All sizes, even very small ones, are used in Native American jewelry, and large sizes have been popular for carvings. For any size, the quality and evenness of the color is the overriding value factor. Simply calculated a carat is 1/5 of a gram of weight so if you have 3 grams it is converted over and equals 15ct.
A single large piece of rough can yield much smaller pieces of fine, evenly colored
turquoise. A gem cutter has to work around the host rock to avoid ending up with a much
less valuable gem.
Enhanced Turquoise Properties
A stone that has undergone treatment to improve its natural state is considered enhanced. There are varying degrees of enhancement; some are very acceptable, other types play a hand in devaluing the market. Pure natural turquoise is not always ideal and it is generally accepted to have some stabilizing. Synthetic turquoise is the most common and cheapest form of turquoise. It is not valuable, because it is pure plastic (1). Reconstituted turquoise is a mix between plastic and turquoise dust, it often looks ok but has a rubbery plastic feel. It receives (2-5) points depending on the quality. Dyes and resins can be injected into a low quality turquoise stone to help stabilize it, and artificially express color (6-12). Professional stabilizing techniques such as the Zachery process are very acceptable. These techniques often leave the finished material harder and more uniform in color. A small amount of oil or wax can be applied to the surface of the stone to help protect it from harmful elements. This is the least invasive form of enhancement and stones receive (13-19) points. Quality natural stone that have not undergone any type of enhancement except polish
To make the surface so something smooth and shinny my rubbing it.
">polishing or rolling receive (20) points. Finally it must be noted that RAW=
A precious stone or metal that has been pulled straight from the earth and has not undergone any processing.
">raw turquoise chalk (infant turquoise) also known as natural carving turquoise is natural ,highly coveted and valued as a jewelry and art medium for thousands of years. This grade/formation was often carved into with Persian symbols and traded as a rune stone , BUT even though it is natural, it is of a RAW quality that can be usable only with a form of oiling or waxing enhancement. Raw turquoise chalk only receives (5) points on the TQI scale when untreated or polished but can be valued much higher ounce I is properly treated using native American techniques which can solidify and crystalize the turquoise naturally leaving it alive and raw while also being hardened and stabilized with no chemicals or additives..
|Enhancement||plastic||reconstituted||heavy stabilization/dyed||pro stabilization waxed/oiled / Zachary process||natural||chalk|
|1 to 20||1||2-5||6-12||13-19||20||5|
Here is a great example of two highly different turqouise / on the right ~ $100.00 , on the left $10,000.00
all based on availability/ rarity/ color/ hue/ style/ size/ and hardness in mohs
Turquoise Value TQI Price per Carat
After you have a total TQI points compare it to the chart below to get the price per carat.