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What is Lapis Lazuli?

Lapis Lazuli Stones

Lapis lazuli, or lapis for short, is a deep-blue metamorphic rock. It is used as a semi-precious stone. It has been prized since antiquity for its intense color. The name comes from the Persian word for the gem, lāžward. Lapis lazuli is a rock composed primarily of lazurite, pyrite, and calcite. As early as the 7th millennium BC, people mined lapis lazuli in the Sar-i Sang mines and in Shortugai. It was also mined in other mines in Badakhshan province in modern northeast Afghanistan. Lapis lazuli artifacts are dated to 7570 BC. They have been found at Bhirrana, which is the oldest site of Indus Valley civilisation. Lapis was highly valued by the Indus Valley Civilisation (3300–1900 BC). Lapis beads have been found at Neolithic burials in Mehrgarh, the Caucasus, and as far away as Mauritania. It was used in the funeral mask of Tutankhamun (1341–1323 BC).

Lapis lazuli has been used since ancient times and remains popular today. This gemstone has been prized for its bright, blue color. It is used for inlay and intarsia. It is also used for pigments for cosmetics and paintings. Its eye appeal is irresistible. Today, jewelry is its predominant use.

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Lapis lazuli value is determined almost exclusively by color. A deep, intense, blue with violet tones would be at the apex. Fine grained, uniform specimens can attain a smooth, highly polished surface not seen in lower grades.

Calcite inclusions almost always lower the value. Pyrite inclusions enhance it in the minds of many collectors and jewelry lovers. Although enthusiasts may debate how much pyrite is ideal in lapis lazuli, most would agree on one thing. The stone is better with less calcite. Calcite can appear as streaks or patches within the darker blue. It can also predominate in the mix, giving the rock an overall lighter blue shade.

Polish quality and faceting artistry also affect value.

The ancient Roman natural historian Pliny the Elder admired lapis lazuli for its colors. He called it “a fragment of the starry firmament,” because it is deep blue with twinkling bits of gold. Lapis lazuli (also simply referred to as lapis) is actually a rock. It is composed of lazurite, haüyne, sodalite, and nosean. These are all members of the sodalite group of minerals. (Lazurite itself may be considered a sulfur-rich haüyne).

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Archeologists have found lapis lazuli beads, jewelry, and carvings at numerous sites, some dating as early as 6,000 BCE. The use of this gem material for art and jewelry probably originated in Afghanistan. It spread to Asia, the Middle East, the Mediterranean, and the Roman world. In the Latin-speaking world of classical antiquity, many gemstones called sapphire or sapphirus may have been pieces of lapis. These names mean “blue stone.” In classical antiquity’s Latin-speaking world, many gemstones called sapphire or sapphirus may have been pieces of lapis. These names mean “blue stone

By the end of the Middle Ages, lapis lazuli began to be exported to Europe. It was ground into powder. The powder was made into the pigment ultramarine. Ultramarine was used by some of the most important artists of the Renaissance and Baroque. These artists include Masaccio, Perugino, Titian, and Vermeer. Ultramarine was often reserved for the clothing of the central figures of their paintings. This was especially true for the Virgin Mary. Ultramarine has also been found in dental tartar of medieval nuns and scribes. This might have been due to them licking their painting brushes while producing medieval texts. It was common when working on manuscripts.

Lapis lazuli usually occurs in crystalline marble as a result of contact metamorphism.

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Lapis takes an excellent polish and can be made into jewellery, carvings, boxes, mosaics, ornaments, small statues, and vases. Interior items and finishing buildings can be also made with lapis. During the Renaissance, lapis was ground and processed to make the pigment ultramarine for use in frescoes and oil painting. Its usage as a pigment in oil paint largely ended during the early 19th century. This change occurred when a chemically identical synthetic variety became available.

Lapis lazuli is commercially synthesized or simulated by the Gillson process. This process is used to make artificial ultramarine and hydrous zinc phosphates. Spinel or sodalite, or dyed jasper or howlite, can be substituted for lapis. (1)

Sources

(1) Wikipedia
(2) Photos by Freepik

In My Shop

Multicolor Lapis Lazuli Bracelets

Multicolor Lapis Lazuli Bracelets

$21.00

These Multicolor Lapis Lazuli Bracelets are composed of 8mm Natural Multicolor Lapis Lazuli Beads and elastic cord

SKU: SJDB156
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What is Aquamarine?

Aquamarine stone

What is Aquamarine? Named after the color of sea water, aquamarine is the blue to blue-green member of the beryl family. Readily available and moderately priced, the modern March birthstone makes an excellent jewelry stone.

White Blue Chocolate Candy Aquamarine [2]

What is the Color of Aquamarine?

This beautiful gem receives its coloring from trace amounts of ferrous iron. Its hues range can range from blueish green, blue-green, greenish blue, to deep blue, and its tones can vary from very light to moderately dark. You’ll rarely see aquamarines darker than a Swiss blue topaz. When you do, the color is usually enhanced by the cut.

You might encounter gemstones sold as “white aquamarines.” Be aware that such stones are most likely colorless beryls, also known as goshenites.

What Does Aquamarine Symbolize?

In Western cultures, due to aquamarine’s color and name, this gem has a folklore strongly connected to the sea. Its mystical purview traditionally includes protection for sailors and fishermen as well as travelers in general.

What Inclusions do Aquamarines Contain?

Inclusions are interesting features of this gemstone. Beryl, and aquamarine in particular, are known for having long, hollow tubes. This distinctive feature can help identify a gem as a member of the beryl family.

Aquamarines may have transparent and metallic inclusions, such as biotite, hematite, ilmenite, phlogopite, pyrite, and  rutile in skeletal crystals. They may also contain crystals of apatite, cassiterite, epidote, garnet, muscovite; quartz, and tourmaline. Some stones contain “snow-stars,” irregularly shaped liquid droplets in a star formation. The Martha Rocha aquamarine has notable “snow-star” inclusions.

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Aquamarine Cat’s Eyes and Star Stones

With enough hollow tube inclusions and proper cutting, aquamarines can show chatoyancy and even asterism. Collectors prize beautiful cat’s eye aquamarines very highly, and their prices come very close to that of clean, faceted gems with the same coloring. Star aquamarines are even more rare than cat’s eyes and can command premium prices.

Are There Lab-Created Aquamarines?

Aquamarines can be synthesized, and an examination under a microscope may find some indications of synthetic origin. However, professional gem labs have advanced instruments that can distinguish natural from created aquamarines.

Are Aquamarine Gemstones Enhanced?

Most aquamarines come out of the ground with a greenish tint, but this will disappear after heating to 375° C, which leaves a pure blue color. Removing aquamarine’s green tinting through heat treatment is very common. In the past, this was done routinely. Nowadays, a more sophisticated public has started appreciating slightly green, untreated aquamarines. However, distinguishing this heating process proves impossible. Therefore, gem graders should describe any pure blue aquamarines as “probably heat treated.”

In the 1970s, Maxixe (pronounced mah-SHE-she), a very dark blue aquamarine, appeared on the market, but the color of this irradiated product wasn’t stable. Although these stones have mostly disappeared from the market, if you’re ever offered a very deep blue aquamarine, buyer beware.

You can distinguish the Maxixe from a natural aquamarine by its lack of pleochroism. Natural aquamarines have distinct blue and colorless dichroism. On the other hand, the Maxixe has no pleochroism. When viewed from any angle, it just shows blue. The absorption spectrum of natural aquamarine and the Maxixe also differs. With a spectroscope, you’ll see a narrow line at 6950, a strong line at 6540, and weak lines at 6280, 6150, 5500, and 5810. This differs considerably from natural aquamarine’s spectrum, with a broad band at 4270 and a diffuse band at 4560.

You can also distinguish a Maxixe aquamarine from a natural stone with a dichroscope. Both windows remain blue when viewing a Maxixe. In contrast, one window should be colorless or pale yellowish when viewing an untreated specimen.

Where are Aquamarine Gemstones Found?

  • Brazil is the world’s major source of fine aquamarine gems. Localities include Minas Gerais, Rio Grande do Norte, Ceara, and others.
  • Madagascar has more than 50 specific localities that produce fine, blue gem material.
  • Other notable sources include the following:
  • United States: San Diego County, California (not much gem material); Mt. Antero, Colorado; Connecticut (some gem); Maine; North Carolina.

Aquamarine Trade Names

  • Brazilian aquamarine: blueish green. Also a misnomer for blueish green topaz.
  • Madagascar aquamarine: fine, medium blue.
  • Maxixe beryl: treated beryl with excellent aquamarine blue, known for fading. Also called halbanite.
  • Santa Maria aquamarine: medium-dark tone and highly saturated blue color.
  • Don’t assume aquamarines billed as “Brazilian” or “Madagascar” actually come from these sources. These terms may only refer to the color, so ask to see documentation to certify a gem’s origin. “Santa Maria” aquamarines are named after the Santa Maria de Itabira mine where they were first discovered, but stones with similar colors have also been found in other locations.

In My Shop

Aquamarine Necklace and Earrings Set

Sources

[1] International Gem Society
[2] Photos by Freepik

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What is Tourmaline?

tourmaline gems

Tourmaline is a name applied to a family of related minerals with widely varying properties. Tourmalines make very popular jewelry stones and comes in an amazing range of colors, like pink, blue, green, yellow, colorless, and black. Stones can also include multi-color zones.

Ready availability keeps tourmaline prices reasonable. Small tourmalines (under 5 carats) are fairly easy to obtain at modest cost. Only when you get into large sizes or extremely rare or fine colors do prices go over a few hundred dollars per carat.

Most colors are fairly common, but pure blue, red, orange, yellow, and purple stones are rare. Such stones usually command higher prices. Color-change tourmalines are also exceptionally rare. Neon-blue paraíba tourmalines, raspberry-red rubellites, and emerald-green chrome tourmalines are especially prized.

Brightly colored Ceylonese gem tourmalines were brought to Europe in great quantities by the Dutch East India Company to satisfy a demand for curiosities and gems. Tourmaline was sometimes called the “Ceylonese Magnet” because it could attract and then repel hot ashes due to its pyroelectric properties.

Tourmalines were used by chemists in the 19th century to polarize light by shining rays onto a cut and polished surface of the gem. 

Schori

The most common species of tourmaline is schorl, the sodium iron (divalent) endmember of the group. It may account for 95% or more of all tourmaline in nature. The early history of the mineral schorl shows that the name “schorl” was in use prior to 1400 because a village known today as Zschorlau (in Saxony, Germany) was then named “Schorl” (or minor variants of this name), and the village had a nearby tin mine where, in addition to cassiterite, black tourmaline was found. The first description of schorl with the name “schürl” and its occurrence (various tin mines in the Ore Mountains) was written by Johannes Mathesius (1504–1565) in 1562 under the title “Sarepta oder Bergpostill”. Up to about 1600, additional names used in the German language were “Schurel”, “Schörle”, and “Schurl”. Beginning in the 18th century, the name Schörl was mainly used in the German-speaking area. In English, the names shorl and shirl were used in the 18th century. In the 19th century the names common schorl, schörl, schorl and iron tourmaline were the English words used for this mineral.

Dravite

Dravite

Dravite, also called brown tourmaline, is the sodium magnesium rich tourmaline endmember. Uvite, in comparison, is a calcium magnesium tourmaline. Dravite forms multiple series, with other tourmaline members, including schorl and elbaite.

The name dravite was used for the first time by Gustav Tschermak (1836–1927), Professor of Mineralogy and Petrography at the University of Vienna, in his book Lehrbuch der Mineralogie (published in 1884) for magnesium-rich (and sodium-rich) tourmaline from village Dobrova near Unterdrauburg in the Drava river area, Carinthia, Austro-Hungarian Empire. Today this tourmaline locality (type locality for dravite) at Dobrova (near Dravograd), is a part of the Republic of Slovenia. Tschermak gave this tourmaline the name dravite, for the Drava river area, which is the district along the Drava River (in German: Drau, in Latin: Drave) in Austria and Slovenia. 

Dravite varieties include the deep green chromium dravite and the vanadium dravite.

Ebalite

A lithium-tourmaline elbaite was one of three pegmatitic minerals from Utö, Sweden, in which the new alkali element lithium (Li) was determined in 1818 by Johan August Arfwedson for the first time. Elba Island, Italy, was one of the first localities where colored and colorless Li-tourmalines were extensively chemically analysed. In 1850, Karl Friedrich August Rammelsberg described fluorine (F) in tourmaline for the first time. In 1870, he proved that all varieties of tourmaline contain chemically bound water.

Color

Tourmaline has a variety of colors. Iron-rich tourmalines are usually black to bluish-black to deep brown, while magnesium-rich varieties are brown to yellow, and lithium-rich tourmalines are almost any color: blue, green, red, yellow, pink, etc. Rarely, it is colorless. Bi-colored and multicolored crystals are common, reflecting variations of fluid chemistry during crystallization. Crystals may be green at one end and pink at the other, or green on the outside and pink inside; this type is called watermelon tourmaline and is prized in jewelry. An excellent example of watermelon tourmaline jewelry is a brooch piece (1969, gold, watermelon tourmaline, diamonds) by Andrew Grima (British, b. Italy, 1921–2007), in the collection of Kimberly Klosterman and on display at the Cincinnati Art Museum. Some forms of tourmaline are dichroic; they change color when viewed from different directions.

The pink color of tourmalines from many localities is the result of prolonged natural irradiation. During their growth, these tourmaline crystals incorporated Mn2+ and were initially very pale. Due to natural gamma ray exposure from radioactive decay of 40K in their granitic environment, gradual formation of Mn3+ ions occurs, which is responsible for the deepening of the pink to red color.

In Our Shop

Watermelon Tourmaline Earrings

Sources

International Gem Society
Wikipedia