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85-534: The Marie Louise Diadem is a diamond and turquoise diadem on permanent display at the National Museum of Natural History in Washington D.C.. It is named for Marie Louise of Austria , the wife of Emperor Napoleon of France . The design of the diadem's shell is very typical of Marie-Étienne Nitot 's work from the period. A closed circle in shape, the diadem is left-right symmetrical, broadest in

170-515: A human skull as their base), knives , and shields . Natural resins , bitumen and wax were used to bond the turquoise to the objects' base material; this was usually wood , but bone and shell were also used. Like the Aztecs, the Pueblo , Navajo and Apache tribes cherished turquoise for its amuletic use; the latter tribe believe the stone to afford the archer dead aim. In Navajo culture it

255-474: A scarab motif, accompanied by carnelian , lapis lazuli , and in later pieces, coloured glass . Turquoise, associated with the goddess Hathor , was so liked by the Ancient Egyptians that it became (arguably ) the first gemstone to be imitated, the fair structure created by an artificial glazed ceramic product known as faience . The French conducted archaeological excavations of Egypt from

340-482: A binder used, meaning it is best described as a simulant rather than a synthetic). Gilson turquoise is made in both a uniform colour and with black "spiderweb matrix" veining not unlike the natural Nevada material. The most common imitation of turquoise encountered today is dyed howlite and magnesite , both white in their natural states, and the former also having natural (and convincing) black veining similar to that of turquoise. Dyed chalcedony , jasper , and marble

425-479: A bringer of good fortune or a talisman. The oldest evidence for this claim was found in Ancient Egypt , where grave furnishings with turquoise inlay were discovered, dating from approximately 3000 BCE. In the ancient Persian Empire , the sky-blue gemstones were earlier worn round the neck or wrist as protection against unnatural death. If they changed colour, the wearer was thought to have reason to fear

510-966: A decline in the Roman Catholic Church 's influence which allowed the use of turquoise in secular jewellery. It was apparently unknown in India until the Mughal period, and unknown in Japan until the 18th century. A common belief shared by many of these civilizations held that turquoise possessed certain prophylactic qualities; it was thought to change colour with the wearer's health and protect him or her from untoward forces. The Aztecs viewed turquoise as an embodiment of fire and gave it properties such as heat and smokiness. They inlaid turquoise, together with gold , quartz , malachite , jet , jade , coral , and shells , into provocative (and presumably ceremonial ) mosaic objects such as masks (some with

595-402: A heated probe may give rise to the pungent smell so indicative of plastic. Differences in specific gravity , refractive index , light absorption (as evident in a material's absorption spectrum ), and other physical and optical properties are also considered as means of separation. Turquoise is treated to enhance both its colour and durability (increased hardness and decreased porosity ). As

680-419: A historical perspective, are Serabit el-Khadim and Wadi Maghareh , believed to be among the oldest of known mines. The former mine is situated about 4 kilometres from an ancient temple dedicated to the deity Hathor . The turquoise is found in sandstone that is, or was originally, overlain by basalt . Copper and iron workings are present in the area. Large-scale turquoise mining is not profitable today, but

765-431: A maximum Mohs 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. X-ray diffraction testing shows its crystal system to be triclinic . With lower hardness comes greater porosity . The lustre of turquoise is typically waxy to subvitreous, and its transparency

850-432: A minor source of turquoise for 3,000 years or more. Gem-quality material, in the form of compact nodules, is found in the fractured, silicified limestone of Yunxian and Zhushan , Hubei province. Additionally, Marco Polo reported turquoise found in present-day Sichuan . Most Chinese material is exported, but a few carvings worked in a manner similar to jade exist. In Tibet , gem-quality deposits purportedly exist in

935-562: A mix of rose-cut and brilliant-cut diamonds. The band that forms the base of the diadem is decorated with an unbroken single row of rose-cut diamonds. In total, the Marie Louise Diadem held seventy-nine Colombian emeralds 'of the highest quality', sourced from the mines of Muzo , along with 1,002 brilliant-cut and 264 rose-cut diamonds of various sizes totalling more than 700 carats (140 g) in weight. The seventy-nine emeralds were later removed and replaced with

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1020-428: A typical turquoise deposit begins with hydrothermal deposition of copper sulfides . This takes place when hydrothermal fluids leach copper from a host rock, which is typically an intrusion of calc-alkaline rock with a moderate to high silica content that is relatively oxidized . The copper is redeposited in more concentrated form as a copper porphyry , in which veins of copper sulfide fill joints and fractures in

1105-458: A uniform dark blue) and texture (usually granular or sugary). Glass and plastic will have a much greater translucency, with bubbles or flow lines often visible just below the surface. Staining between grain boundaries may be visible in dyed imitations. Some destructive tests may be necessary; for example, the application of diluted hydrochloric acid will cause the carbonates odontolite and magnesite to effervesce and howlite to turn green, while

1190-441: A wetting effect, thereby enhancing the colour and lustre. This treatment is more or less acceptable by tradition, especially because treated turquoise is usually of a higher grade to begin with. Oiled and waxed stones are prone to "sweating" under even gentle heat or if exposed to too much sun, and they may develop a white surface film or bloom over time. (With some skill, oil and wax treatments can be restored.) Since finer turquoise

1275-435: Is less common, and much less convincing. Other natural materials occasionally confused with or used in lieu of turquoise include: variscite and faustite ; chrysocolla (especially when impregnating quartz ); lazulite ; smithsonite ; hemimorphite ; wardite ; and a fossil bone or tooth called odontolite or "bone turquoise", coloured blue naturally by the mineral vivianite . While rarely encountered today, odontolite

1360-510: Is nearly always cryptocrystalline and massive and assumes no definite external shape. Crystals, even at the microscopic scale, are rare. Typically the form is a vein or fracture filling, nodular, or botryoidal in habit . Stalactite forms have been reported. Turquoise may also pseudomorphously replace feldspar, apatite, other minerals, or even fossils . Odontolite is fossil bone or ivory that has historically been thought to have been altered by turquoise or similar phosphate minerals such as

1445-407: Is of a low grade (called "chalk turquoise"); high iron levels mean greens and yellows predominate, and a typically friable consistency in the turquoise's untreated state precludes use in jewelry . Arizona is currently the most important producer of turquoise by value. Several mines exist in the state, two of them famous for their unique colour and quality and considered the best in the industry:

1530-544: Is often found as thin seams, it may be glued to a base of stronger foreign material for reinforcement. These stones are termed "backed", and it is standard practice that all thinly cut turquoise in the Southwestern United States is backed. Native indigenous peoples of this region, because of their considerable use and wearing of turquoise, have found that backing increases the durability of thinly cut slabs and cabochons of turquoise. They observe that if

1615-468: Is restricted to a mine-riddled region in Nishapur , the 2,012 m (6,601 ft) mountain peak of Ali-mersai near Mashhad , the capital of Khorasan Province , Iran . Weathered and broken trachyte is host to the turquoise, which is found both in situ between layers of limonite and sandstone and amongst the scree at the mountain's base. These workings are the oldest known, together with those of

1700-428: Is so often the case with any precious stones, full disclosure about treatment is frequently not given. Gemologists can detect these treatments using a variety of testing methods, some of which are destructive, such as the use of a heated probe applied to an inconspicuous spot, which will reveal oil, wax or plastic treatment. Historically, light waxing and oiling were the first treatments used in ancient times, providing

1785-611: Is termed "bonded" or "stabilized" turquoise. This process consists of pressure impregnation of otherwise unsaleable chalky American material by epoxy and plastics (such as polystyrene ) and water glass (sodium silicate) to produce a wetting effect and improve durability. Plastic and water glass treatments are far more permanent and stable than waxing and oiling, and can be applied to material too chemically or physically unstable for oil or wax to provide sufficient improvement. Conversely, stabilization and bonding are rejected by some as too radical an alteration. The epoxy binding technique

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1870-458: Is the cause of the beautiful bright green to yellow-green shades. Some of the green to green-yellow shades may actually be variscite or faustite , which are secondary phosphate minerals similar in appearance to turquoise. A significant portion of the Nevada material is also noted for its often attractive brown or black limonite veining, producing what is called "spiderweb matrix". While a number of

1955-482: Is the country's other major producer, with more than 120 mines which have yielded significant quantities of turquoise. Unlike elsewhere in the US, most Nevada mines have been worked primarily for their gem turquoise and very little has been recovered as a byproduct of other mining operations. Nevada turquoise is found as nuggets , fracture fillings and in breccias as the cement filling interstices between fragments. Because of

2040-540: Is thought to be the location of the oldest mines; prior to the 1920s, the state was the country's largest producer; it is more or less exhausted today. Only one mine in California, located at Apache Canyon, operates at a commercial capacity today. The turquoise occurs as vein or seam fillings, and as compact nuggets; these are mostly small in size. While quite fine material is sometimes found, rivalling Iranian material in both colour and durability, most American turquoise

2125-440: Is treated only for porosity, the treatment is undetectable. The use of Prussian blue and other dyes (often in conjunction with bonding treatments) to "enhance” its appearance, make uniform or completely change the colour, is regarded as fraudulent by some purists, especially since some dyes may fade or rub off on the wearer. Dyes have also been used to darken the veins of turquoise. Material treated with plastic or water glass

2210-772: Is typically the most translucent, and under magnification, its surface structure is revealed to be peppered with dark blue discs not seen in material from other localities. The Southwest United States is a significant source of turquoise; Arizona , California ( San Bernardino , Imperial , Inyo counties), Colorado ( Conejos , El Paso , Lake , Saguache counties), New Mexico ( Eddy , Grant , Otero , Santa Fe counties) and Nevada ( Clark , Elko , Esmeralda County , Eureka , Lander , Mineral County and Nye counties) are (or were) especially rich. The deposits of California and New Mexico were mined by pre-Columbian Native Americans using stone tools, some local and some from as far away as central Mexico . Cerrillos , New Mexico

2295-474: Is used for "a spiritual protection and blessing." Among these peoples turquoise was used in mosaic inlay, in sculptural works, and was fashioned into toroidal beads and freeform pendants. The Ancestral Puebloans (Anasazi) of the Chaco Canyon and surrounding region are believed to have prospered greatly from their production and trading of turquoise objects. The distinctive silver jewellery produced by

2380-407: 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 iron impurities (replacing copper.) The refractive index of turquoise varies from 1.61 to 1.65 on

2465-631: The Aztecs (and possibly other Pre-Columbian Mesoamericans ), Persia , Mesopotamia , the Indus Valley , and to some extent in ancient China since at least the Shang dynasty . Despite being one of the oldest gems, probably first introduced to Europe (through Turkey ) with other Silk Road novelties, turquoise did not become important as an ornamental stone in the West until the 14th century, following

2550-711: The Cerrillos Hills in New Mexico, are typical supergene deposits formed from copper porphyries. The deposits in Cochise County, Arizona , are found in Cambrian quartzites and geologically young granites and go down at least as deep as 54 meters (177 ft). Turquoise was among the first gems to be mined, and many historic sites have been depleted, though some are still worked to this day. These are all small-scale operations, often seasonal owing to

2635-566: The Earth's surface ) percolates through the copper porphyry. Dissolved oxygen in the water oxidizes the copper sulfides to soluble sulfates, and the acidic, copper-laden solution then reacts with aluminum and potassium minerals in the host rock to precipitate turquoise. This typically fills veins in volcanic rock or phosphate-rich sediments. Deposition usually takes place at a relatively low temperature, 90–195 °C (194–383 °F), and seems to occur more readily in arid environments. Turquoise in

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2720-521: The First Dynasty and possibly earlier; however, probably the most well-known pieces incorporating the gem are those recovered from Tutankhamun 's tomb, most notably the Pharaoh 's iconic burial mask which was liberally inlaid with the stone. It also adorned rings and great sweeping necklaces called pectorals . Set in gold, the gem was fashioned into beads, used as inlay, and often carved in

2805-627: The Galerie d’Apollon . The Marie Louise Diadem was returned to Van Cleef & Arpels after the 1962 exhibition. They lent it out to Marjorie Merriweather Post to wear to a fundraising ball for the Red Cross in Palm Beach, Florida in 1967, where it received a great amount of acclaim. When the firm later wrote to Post in 1971 offering her the opportunity to buy the diadem through a private sale before they began looking for clients, she donated

2890-558: The Sinai Peninsula is found in lower Carboniferous sandstones overlain by basalt flows and upper Carboniferous limestone . The overlying beds were presumably the source of the copper, which precipitated as turquoise in nodules, horizontal seams, or vertical joints in the sandstone beds. The classical Iranian deposits are found in sandstones and limestones of Tertiary age were intruded by apatite -rich porphyritic trachytes and mafic rock. Supergene alteration fractured

2975-688: The Sinai Peninsula . Iran also has turquoise mines in Semnan and Kerman provinces. Since at least the First Dynasty (3000  BCE ) in ancient Egypt , and possibly before then, turquoise was used by the Egyptians and was mined by them in the Sinai Peninsula . This region was known as the Country of Turquoise by the native Monitu . There are six mines in the peninsula, all on its southwest coast, covering an area of some 650 km (250 sq mi). The two most important of these mines, from

3060-530: The Smithsonian Institution and the Louvre , who later owned pieces from the parure, put the gift as being presented on the day of the imperial wedding in 1810. Of mixed use as circumstantial evidence of the latter theory, a portrait of Marie Louise wearing a diadem of the design was painted by Jean-Baptiste Isabey in 1810 (see right). However, the painter may not have been working from life, as

3145-588: The 17th century and is derived from the Old French turquois meaning "Turkish" because the mineral was first brought to Europe through the Ottoman Empire . However, according to Etymonline , the word dates to the 14th century with the form turkeis , meaning "Turkish", which was replaced with turqueise from French in the 1560s. According to the same source, the gemstone was first brought to Europe from Turkestan or another Turkic territory. Pliny

3230-618: The 1980s to improve the stability of medium to high-grade turquoise. The process can be applied in several ways: either through deep penetration on rough turquoise to decrease porosity, by shallow treatment of finished turquoise to enhance color, or both. The treatment can enhance color and improve the turquoise's ability to take a polish. Such treated turquoise can be distinguished in some cases from natural turquoise, without destruction, by energy-dispersive X-ray spectroscopy , which can detect its elevated potassium levels. In some instances, such as with already high-quality, low-porosity turquoise that

3315-580: The American Southwest. The pre-Columbian Aztec and Maya also considered it to be a valuable and culturally important stone. The Egyptians were the first to produce an artificial imitation of turquoise, in the glazed earthenware product faience . Later glass and enamel were also used, and in modern times more sophisticated porcelain , plastics , and various assembled, pressed, bonded, and sintered products (composed of various copper and aluminium compounds) have been developed: examples of

3400-490: The Elder referred to the mineral as callais (from Ancient Greek κάλαϊς ) and the Aztecs knew it as chalchihuitl . In professional mineralogy, until the mid-19th century, the scientific names kalaite or azure spar were also used, which simultaneously provided a version of the mineral origin of turquoise. However, these terms did not become widespread and gradually fell out of use. The finest of turquoise reaches

3485-563: The Native American style, or as tumbled or roughly hewn beads in chunky necklaces. Lesser material may be carved into fetishes , such as those crafted by the Zuni . While strong sky blues remain superior in value, mottled green and yellowish material is popular with artisans . In many cultures of the Old and New Worlds, this gemstone has been esteemed for thousands of years as a holy stone,

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3570-601: The Navajo and other Southwestern Native American tribes today is a rather modern development, thought to date from around 1880 as a result of European influences. In Persia, turquoise was the de facto national stone for millennia, extensively used to decorate objects (from turbans to bridles ), mosques , and other important buildings both inside and out, such as the Medresseh-i Shah Husein Mosque of Isfahan . The Persian style and use of turquoise

3655-612: The Nevada deposits were first worked by Native Americans, the total Nevada turquoise production since the 1870s has been estimated at more than 600 short tons (540 t), including nearly 400 short tons (360 t) from the Carico Lake mine. In spite of increased costs, small scale mining operations continue at a number of turquoise properties in Nevada, including the Godber, Orvil Jack and Carico Lake mines in Lander County,

3740-656: The Pilot Mountain Mine in Mineral County , and several properties in the Royston and Candelaria areas of Esmerelda County. In 1912, the first deposit of distinct, single-crystal turquoise was discovered at Lynch Station in Campbell County , Virginia . The crystals, forming a druse over the mother rock, are very small; 1 mm (0.04 in) is considered large. Until the 1980s Virginia

3825-578: The Sleeping Beauty Mine in Globe ceased turquoise mining in August 2012. The mine chose to send all ore to the crusher and to concentrate on copper production due to the rising price of copper on the world market. The price of natural untreated Sleeping Beauty turquoise has risen dramatically since the mine's closing. The Kingman Mine as of 2015 still operates alongside a copper mine outside of

3910-404: The approach of doom. Meanwhile, it has been discovered that the turquoise certainly can change colour, but that this is not necessarily a sign of impending danger. The change can be caused by the light, or by a chemical reaction brought about by cosmetics, dust or the acidity of the skin. The goddess Hathor was associated with turquoise, as she was the patroness of Serabit el-Khadim , where it

3995-672: The article/advertisement of the emeralds in Life magazine in January 1955, Van Cleef & Arpels' secretary, Fred Vermont, told the United Press, "In 24 hours, we were sold out of emeralds. And we are still flooded with orders…letters and telegrams from all over the country." One such brooch, set with nine of the diadem's emeralds, has been put up for auction at Christie's several times since its original purchase; it sold for $ 178,500 in 1999, and again for $ 450,000 in 2014. As each emerald

4080-721: The buyer on sale of the material. Turquoise prehistoric artifacts (beads) are known since the fifth millennium BCE from sites in the Eastern Rhodopes in Bulgaria – the source for the raw material is possibly related to the nearby Spahievo lead–zinc ore field. In Spain, turquoise has been found as a minor mineral in the variscite deposits exploited during prehistoric times in Palazuelos de las Cuevas (Zamora) and in Can Tintorer, Gavá (Barcelona). China has been

4165-514: The city. Other mines include the Blue Bird mine, Castle Dome, and Ithaca Peak, but they are mostly inactive due to the high cost of operations and federal regulations. The Phelps Dodge Lavender Pit mine at Bisbee ceased operations in 1974 and never had a turquoise contractor. All Bisbee turquoise was "lunch pail" mined. It came out of the copper ore mine in miners' lunch pails. Morenci and Turquoise Peak are either inactive or depleted. Nevada

4250-453: The deposits are sporadically quarried by Bedouin peoples using homemade gunpowder . In the rainy winter months, miners face a risk from flash flooding ; even in the dry season, death from the collapse of the haphazardly exploited sandstone mine walls may occur. The colour of Sinai material is typically greener than that of Iranian material but is thought to be stable and fairly durable. Often referred to as "Egyptian turquoise", Sinai material

4335-537: The diadem and its associated jewelry pieces with her, where the crown jewels were left behind. The diadem was designed by Marie-Étienne Nitot , the official court jeweler of Emperor Napoleon, and produced by his company in Paris, The House of Chaumet . Nitot had been commissioned to create several other pieces for the Emperor in the past, including Napoleon's papal tiara , his coronation crown, his ceremonial sword and

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4420-488: The diadem precluded any further replacement, however. Turquoise Like most other opaque gems, turquoise has been devalued by the introduction of treatments, imitations, and synthetics into the market. The robin egg blue or sky blue color of the Persian turquoise mined near the modern city of Nishapur , Iran , has been used as a guiding reference for evaluating turquoise quality. The word turquoise dates to

4505-440: The diadem was put on display in the Louvre in 1962, alongside the necklace, earrings and comb tiara from the original parure, as part of the 'Dix Siecles de Joaillerie Francaise' exhibition, celebrating French jewelry from the past millennium. The Louvre went on to purchase the necklace and earrings from their owners in 2004 for €3.7m, the highest price ever paid by a museum for individual pieces of jewelry. They remain on display in

4590-428: The emeralds were divided amongst six pieces—two sets of earrings, a bracelet, a ring, a clip, and a necklace. These used platinum settings and more modern brilliant cut diamonds, and were valued as a set at around $ 1m. The smaller emeralds from the diadem were mounted piecemeal into individual pieces and sold at various price points, some as low as $ 300, advertised as "emeralds from the historic Napoleon Tiara." Following

4675-440: The front and narrowing towards the rear. Nitot made elaborate use of scrollwork , medallions , as well as palmettes and other floral motifs, rendered in silver and gold. In this it is similar to diadems and tiaras he produced for Marie-Thérèse, Duchess of Angoulême and Princess Augusta of Bavaria . The centrepiece at the front of the diadem was originally a single large square-cut emerald, aligned with one of its diagonals along

4760-453: The geology of the Nevada deposits, a majority of the material produced is hard and dense, being of sufficient quality that no treatment or enhancement is required. While nearly every county in the state has yielded some turquoise, the chief producers are in Lander and Esmeralda counties . Most of the turquoise deposits in Nevada occur along a wide belt of tectonic activity that coincides with

4845-477: The iron phosphate vivianite . Intergrowth with other secondary copper minerals such as chrysocolla is also common. Turquoise is distinguished from chrysocolla, the only common mineral with similar properties, by its greater hardness. Turquoise forms a complete solid solution series with chalcosiderite , CuFe 6 (PO 4 ) 4 (OH) 8 ·4H 2 O , in which ferric iron replaces aluminium. Turquoise deposits probably form in more than one way. However,

4930-439: The jewels' long history within the family and the claimed original provenance. The remaining pieces of the parure were later sold separately by the family in private sales. Van Cleef & Arpels put both the diadem and belt buckle on display in the window of their New York store. At some point after, the firm took them down from display to remove the emeralds from both and re-set them into individual pieces of jewelry. The largest of

5015-412: The latter include "Viennese turquoise", made from precipitated aluminium phosphate coloured by copper oleate ; and "neolith", a mixture of bayerite and copper(II) phosphate . Most of these products differ markedly from natural turquoise in both physical and chemical properties, but in 1972 Pierre Gilson introduced one fairly close to a true synthetic (it does differ in chemical composition owing to

5100-487: The limited scope and remoteness of the deposits. Most are worked by hand with little or no mechanization. However, turquoise is often recovered as a byproduct of large-scale copper mining operations, especially in the United States. Deposits typically take the form of small veins in partially decomposed volcanic rock in arid climates. Iran has been an important source of turquoise for at least 2,000 years. It

5185-455: The median line, which weighed 12 carats (2.4 g). A smaller oval-cut emerald was placed directly below the largest stone, and was in turn framed by five smaller rose-cut emeralds. Surrounding the centrepiece is a single layer of rose-cut white diamonds. Twenty large emeralds were set into the symmetrical floral and scrollwork decorations, cut in oval and briolette forms, and fifty-two smaller rose-cut and square-cut emeralds, also framed by

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5270-462: The mid-19th century through the early 20th. These excavations, including that of Tutankhamun's tomb, created great public interest in the western world, subsequently influencing jewellery, architecture , and art of the time. Turquoise, already favoured for its pastel shades since around 1810, was a staple of Egyptian Revival pieces. In contemporary Western use, turquoise is most often encountered cut en cabochon in silver rings, bracelets, often in

5355-422: The mountains of Derge and Nagari-Khorsum in the east and west of the region respectively. Other notable localities include: Afghanistan ; Australia ( Victoria and Queensland ); north India ; northern Chile ( Chuquicamata ); Cornwall ; Saxony ; Silesia ; and Turkestan . The pastel shades of turquoise have endeared it to many great cultures of antiquity: it has adorned the rulers of Ancient Egypt ,

5440-535: The nude teenager take a bath. She was then redressed in only the clothes and jewels purchased for her by her new husband. As such, with no jewelry of her own, Marie Louise needed an entire new set produced for her. Among these were a pair of parures , one in diamond and opal, one in diamond and emerald. It is to the latter set that the later-named Marie Louise Diadem belonged. Both sets were given to Marie Louise to keep as part of her personal collection. As such, when she left Paris for Vienna after Napoleon's exile, she took

5525-778: The painting depicts the diadem as holding rubies instead of emeralds. Upon Marie Louise's death in 1847, her jewels were divided among her Habsburg relatives , her son having pre-deceased her. There is some disagreement over the exact path down the family tree that the diadem and its parure took: The reason for the unclear provenance between Marie Louise and Albrecht lies in the loss of the family's papers and documentation when Albrecht and his family fled Poland after being interned by Nazi Germany in World War II . After his death in Stockholm in 1951, Albrecht's widow ( Alice Habsburg ) and son ( Archduke Karl Stefan of Austria ) began

5610-497: The process of selling the family jewels, including the diadem, to various jewelers. However, with the documentation for the jewels lost during the flight from Poland, finding buyers proved difficult. Eventually, the New York-based jewelry firm Van Cleef & Arpels purchased the Marie Louise Diadem and its matching belt buckle from the family in 1953, accepting the signed affidavit of both Alice and Karl Stefan attesting to

5695-691: The requested funds to the Smithsonian Institution to allow them to purchase it at the stated price. The Smithsonian Institution have had the diadem on display in the National Museum of Natural History ever since, in the Janet Hooker Hall of Gems and Geology. It was temporarily removed from its shared display alongside the Napoleon Diamond Necklace for several months in the 1990s while the diadem

5780-591: The rock and converted some of the minerals in the rock to alunite , which freed aluminum and phosphate to combine with copper from oxidized copper sulfides to form turquoise. This process took place at a relatively shallow depth, and by 1965 the mines had "bottomed" at a depth averaging just 9 meters (30 ft) below the surface. Turquoise deposits are widespread in North America. Some deposits, such as those of Saguache and Conejos Counties in Colorado or

5865-416: The rock. Deposition takes place mostly in the potassic alteration zone, which is characterized by conversion of existing feldspar to potassium feldspar and deposition of quartz and micas at a temperature of 400–600 °C (752–1,112 °F) Turquoise is a secondary or supergene mineral, not present in the original copper porphyry. It forms when meteoric water (rain or snow melt infiltrating

5950-585: The same number of Iranian turquoise stones, cut as cabochons rather than faceted like the original emeralds. The turquoise replacement stones weigh a total of 540 carats (108 g). Tradition dictated that a royal bride coming to France must keep nothing of her homeland, especially her clothes. Accordingly, when Marie Louise of Austria arrived in France to marry Emperor Napoleon, she was stripped of her dress, corset, stockings, and chemise, leaving her completely naked. Pauline Bonaparte , Napoleon's sister, then made

6035-408: The set on several state occasions. There is some disagreement over the exact date the diadem was presented to Marie Louise. The jewelers Van Cleef & Arpels , who purchased the diadem in the mid 20th century, reported to Life magazine that Napoleon had gifted the diamond and emerald parure to her in celebration of the birth of her son, Napoléon François Joseph Charles Bonaparte , in 1811. Both

6120-407: The silver and gold jewellery of Tibet and Mongolia , where a greener hue is said to be preferred. Most of the pieces made today, with turquoise usually roughly polished into irregular cabochons set simply in silver, are meant for inexpensive export to Western markets and are probably not accurate representations of the original style. The Ancient Egyptian use of turquoise stretches back as far as

6205-457: The state's zone of thrust faulting . It strikes at a bearing of about 15° and extends from the northern part of Elko County , southward down to the California border southwest of Tonopah . Nevada has produced a wide diversity of colours and mixes of different matrix patterns, with turquoise from Nevada coming in various shades of blue, blue-green, and green. Some of this unusually-coloured turquoise may contain significant zinc and iron , which

6290-480: The stone is not backed it will often crack. Backing of turquoise is not widely known outside of the Native American and Southwestern United States jewellery trade. Backing does not diminish the value of high quality turquoise, and indeed the process is expected for most thinly cut American commercial gemstones. A proprietary process was created by electrical engineer and turquoise dealer James E. Zachery in

6375-461: The three crystal axes, with birefringence 0.040, biaxial positive, as measured from rare single crystals. Crushed turquoise is soluble in hot hydrochloric acid . Its streak is white to greenish to blue, and its fracture is smooth to conchoidal . Despite its low hardness relative to other gems, turquoise takes a good polish. Turquoise may also be peppered with flecks of pyrite or interspersed with dark, spidery limonite veining. Turquoise

6460-575: The trade reconstituted turquoise is often called "block turquoise" or simply "block". Hardness and richness of colour are two of the major factors in determining the value of turquoise; while colour is a matter of individual taste, generally speaking, the most desirable is a strong sky to robin egg blue (in reference to the eggs of the American robin ). Whatever the colour, for many applications, turquoise should not be soft or chalky; even if treated, such lesser material (to which most turquoise belongs)

6545-416: The wedding jewels of his first wife, Josephine de Beauharnais . In this case, the commissioned diadem was to be the centrepiece of a parure for Napoleon's second wife, Marie Louise of Austria. The parure also included matching earrings, a necklace, a comb tiara and a belt buckle, all designed in silver and gold, decorated with emeralds and diamonds, and using the same stylistic flourishes. Marie Louise wore

6630-480: Was first developed in the 1950s and has been attributed to Colbaugh Processing of Arizona, a company that still operates today. Perhaps the most extreme of treatments is "reconstitution", wherein fragments of fine turquoise material, too small to be used individually, are powdered and then bonded with resin to form a solid mass. Very often the material sold as "reconstituted turquoise" is artificial , with little or no natural stone, made entirely from resins and dyes. In

6715-523: Was initially named by Iranians " pērōzah " meaning "victory", and later the Arabs called it " fayrūzah ", which is pronounced in Modern Persian as " fīrūzeh ". In Iranian architecture, the blue turquoise was used to cover the domes of palaces because its intense blue colour was also a symbol of heaven on earth. This deposit is blue naturally and turns green when heated due to dehydration. It

6800-592: Was later brought to India following the establishment of the Mughal Empire there, its influence seen in high purity gold jewellery (together with ruby and diamond ) and in such buildings as the Taj Mahal . Persian turquoise was often engraved with devotional words in Arabic script which was then inlaid with gold. Cabochons of imported turquoise, along with coral, was (and still is) used extensively in

6885-535: Was mined. Her titles included "Lady of Turquoise", "Mistress of Turquoise", and "Lady of Turquoise Country". In Western culture, turquoise is also the traditional birthstone for those born in the month of December. The turquoise is also a stone in the Jewish High Priest 's breastplate , described in Exodus chapter 28. The stone is also considered sacred to the indigenous Zuni and Pueblo peoples of

6970-504: Was once mined in large quantities—specifically for its use as a substitute for turquoise—in southern France . These fakes are detected by gemologists using a number of tests, relying primarily on non-destructive, close examination of surface structure under magnification; a featureless, pale blue background peppered by flecks or spots of whitish material is the typical surface appearance of natural turquoise, while manufactured imitations will appear radically different in both colour (usually

7055-419: Was passed to a conservator-restorer for restoration. During that restoration, the antique frame was disassembled, cleaned, and re-assembled, with damaged portions soldered . After facilitating the purchase, Post inquired about the possibility of replacing the turquoise with emeralds once again, either artificial or—if possible to collect from their new owners—the original gemstones themselves. The fragility of

7140-479: Was sold, Van Cleef & Arpels replaced it in the original diadem with turquoise sourced from Iran (then Persia). Jeffrey Edward Post, Curator of the U.S. National Gem and Mineral Collection, speculates that turquoise was chosen as it was relatively inexpensive and easy to shape to match the original settings, while the Louvre claim it was done by request of Marjorie Merriweather Post . It was with these new stones that

7225-550: Was widely thought to be the only source of distinct crystals; there are now at least 27 other localities. In an attempt to recoup profits and meet demand, some American turquoise is treated or enhanced to a certain degree. These treatments include innocuous waxing and more controversial procedures, such as dyeing and impregnation (see Treatments ). There are some American mines which produce materials of high enough quality that no treatment or alterations are required. Any such treatments which have been performed should be disclosed to

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