Gemstones

The Garnet

Garnet minerals can be found in virtually all colors. There are six types of garnet gems: almandine, andradite, grossular, pyrope, spessartine and uvarovite.

Typically, garnet is known for the dark-to-wine red color that appears in many jewelry pieces, but that is not its most valuable color.

Garnet is quite common in the red, orange, yellow, green, purple, brown, black and pink colors, but the blue pieces are the rarest and most expensive gems.

Color changing is one of the garnet's particular characteristic. Under incandescent light, garnet stones can go from gray to red. These nesosilicates occupy a level between 6.5 to 7.5 on the Mohs scale and, when they fracture, you can easily identify sharp and irregular parts.

The study of garnet examples in the metamorphic rocks allows scientists to understand the age and temperature of the host structure clearly. The largest garnet crystal ever found weighed 37.5 tons and measured 2.3 meters.

Although red garnet is very popular in ancient and contemporary jewelry, this gem has also been used as an abrasive to cut steel and in water filtration.

Garnet is mined for a long time in Rajasthan, India, and can also be found in Australia, USA, and China.

Red garnets were used in the famous "cloisonné technique," a unique skill for decorating metalwork objects. Today, the star garnet is the state gemstone of Idaho.

Only the purest forms of garnet crystals are used in high-end jewelry.

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The Turquoise

One of the first stones to be mined by man, the unforgettable turquoise is a green to sky blue aggregate of hydrated copper and aluminum phosphate.

The name turquoise derives from the French piers turques, meaning "Turkish stone", and refers to the trade route, via Turkey, that brought the gem from Asia to Europe.

It is one of the most ancient gemstones: turquoise beads from 5000bc were found in Mesopotamia, and it was mined by the Egyptians in the Sinai Peninsula before the 4th century BC. It was also the national gemstone of Persia and an important part of the Native American culture.

Turquoise occurs in dense, massive or microcrystalline forms, as nodules, encrustations or in veins, and crystals are rare. The gem is opaque to semi-translucent, and the color ranges from pale green to bright grass green or vivid sky blue, depending on the amounts of iron and copper in the stone.

Top-quality turquoise is intense and evenly colored, with no traces of rock matrix. However, turquoise gems with a delicate, attractive and evenly distributed spiderweb pattern are also valued.

Finely textured, less porous turquoise is more valuable and displays a more attractive luster and better toughness than the more porous and coarser specimens. The later are often treated with artificial resins or wax to improve color and hardness ("stabilized" turquoise).

Nishapur, in northeast Iran, is the source of the best-quality turquoise and is the place where the stunning and highly desirable sky blue Persian Turquoise can be found. Before World War I, turquoise was the main export of Iran.

Other deposits are in Africa, Australia, Siberia, Mexico, Chile, England, China and the USA (New Mexico, Arizona).

Although sky-blue is usually the most prized color of turquoise, in Tibet the greener variety is preferred. This light and fragile gemstone has a moderate hardness, ranking from 5 to 6 on the Mohs scale of hardness. It is usually cut en cabochon or as beads and is also carved or engraved.

Care must be taken when handling turquoise gems and jewelry, because, due to its porosity, it is sensitive to body oils, high temperatures, cosmetics, and detergents. Turquoise rings, for example, should be removed before washing the hands.

Turquoise can be confused with amazonite, lazulite, chrysocolla and hemimorphite. It is imitated by dying other gems such as chalcedony or hoplite, and by baking powdered turquoise pieces with glue.

The mystical azure color of turquoise, along with its strong appearance and soft touch, made it the stone of warriors, kings, and xamans. The birthstone of December is believed to be a gem of protection and good luck since ancient times and was often used as an amulet.

The Turquoise | Physical Properties

Chemical Composition: CuAl6(PO4)4(OH)8.4H2O
Cleavage: Good
Color: Blue, Green
Crystal System: Triclinic
Fracture: Conchoidal
Lustre: Waxy to Dull
Mohs Hardness: 5-6
Specific Gravity: 2.6-2.8
Transparency: Translucent, Opaque

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The Jade

The name jade applies to two different metamorphic rocks: nephrite and jadeite.

Considered more valuable than gold in pre-Columbian Central America, and used in tools and weapons in prehistorical times because of its extraordinary toughness, jade is one of the most ancient and relevant gemstones.

The name jade derives from the Spanish piedra de ijada ("hip stone"), because of its reputation as a protection stone and a cure for kidney ailments. The word nephrite derives from the Latin lapis nephriticus, meaning the same as piedra de ijada.

Jadeite is a mineral of the pyroxene group, composed of interlocking granular crystals. It is white in its purest form, but also occurs in many attractive colors, most notably green (colored by iron) and lilac (colored by manganese and iron), as well as brown, pink, red, blue, black, yellow or orange.

Jadeite has a smooth, soft texture, and can be opaque to semi-transparent. The most precious form of jadeite is semi-transparent with a vibrant emerald-green color, also known as imperial jade.

Nephrite, more common and less expensive than jadeite, is a tough and compact variety of either actinolite or amphibole trimolite. It is even tougher than jadeite and stronger than steel, because of its structure of tightly interlocking fibers. For this reason, nephrite was used in weapons and tools in prehistoric times.

The color of nephrite varies according to its composition and is less diverse than jadeite. It can be dark green (when iron-rich), light brown or cream colored (when magnesium rich). Like jadeite, green is the most valuable color. White nephrite is called "mutton-fat jade."

The primary source of jadeite is Myanmar, where the precious imperial jade can be found and where ancient jadeite weapons and tool were discovered. Other deposits are in Japan and California. New Zealand is the principal source of nephrite, where it occurs in serpentine rocks and as river or beach pebbles. Australia, Brazil, China, Canada, Alaska, California (USA), and Russia.

Jadeite's hardness varies between a 6 and a 7 on the Mohs scale, while nephrite has a hardness of 6. Despite their hardness, both gems are extremely tough. They are rarely faceted and are usually cut en cabochon, as beads or carved.

The history of jade is ancient. Nephrite has been used and cherished in China for over 8000 years, where it was called yu, and its carving evolved into a cultural and artistic tradition. In prehistoric and historic China, jade was used in ceremonial objects, decorative items, and burial suits, and was seen as a godly and imperial gem.

The use of nephrite was also documented in neolithic and chalcolitihic Europe and still plays a significant role in the Maori culture, in New Zealand. The Maori culture considers nephrite jade a treasure, and strictly controls its exploitation. The Maori people used nephrite tools, weapons, and ornaments.

Jadeite, on the other hand, is connected to the Indians of Mexico, Central, and South America, where it was considered sacred and more highly valued than gold. Mesoamerican jadeite came mostly from deposits in Costa Rica and Guatemala.

When the Spanish reached Mexico, they brought jadeite back to Europe, believing it was the same jade used in Europe at the time, which was, in fact, nephrite. Only in 1863, when a Chinese carving was analyzed, the difference between the new world and the old world jades was discovered.

Jadeite from Myanmar was the first to reach China in the late 1700s and a preference for jadeite eventually developed. The Chinese jade carvings are true masterpieces of unmatchable artistry.

The ancient lure of jade persists until today. It was revered in pre-Columbian Central America and has been the most esteemed gem to the Chinese for its beauty, healing powers and protection abilities.

Jade is seen as a tool to access the spiritual world, a strong protection talisman and a stone of friendship, tranquility and truth. It is also seen as a powerful healing stone with medicinal properties: both jadeite and nephrite are believed to heal and prevent kidney problems.

The Jade | Physical Properties

Chemical Composition: Na(Al,Fe) Si2 O6
Cleavage: Good
Color: Emerald-Green, Light Brown, White, Red, Orange, Black
Crystal System: Monoclinic
Fracture: Splintery
Lustre: Vitreous
Mohs Hardness: 6.0.-7.0
Specific Gravity: 2.90-3.10
Transparency: Semi-Transparent

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The Malachite

Malachite is a vibrant green copper carbonate hydroxide, and possibly the earliest ore of copper. Despite its low hardness, the striking color of malachite and its unique patterns make it a beautiful decorative and ornamental stone.

The name malachite comes from the Greek word malache, meaning "mallow," due to the resemblance of the gem to the green leaves of the mallow plant.

The green mineral has been mined in the eastern and Sinai deserts since 3000bc. It was used as a pigment in paints, but today its main use is as a gemstone and ornamental stone.

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The Tranquillityite

Tranquillityite is one of the three lunar minerals found in the rock samples brought by the Apollo 11 mission, in 1969.

Initially, it was thought to be unique to the moon, but in recent years tranquillityite has also been found on Earth.

Tranquillityite is a silicate mineral mostly composed of iron, oxygen, silicon, zirconium, and titanium, with small traces of the rare earth element yttrium, and calcium. The lunar stone was named after the Mare Tranquillitatis (Sea of Tranquility), the site of the first moon landing.

Along with pyroxferroite and armalcolite, tranquillityite is one of the three minerals found on the moon which had never been seen on earth.

The first two were eventually identified on the earth's surface over the next ten years, but tranquillityite remained as a mineral unique to the satellite, with no terrestrial equivalent, found only in moon rock samples and lunar meteorites.

In 2011, small samples, just microns in length, were eventually found in six locations in the Pilbara region, in Western Australia.

Tranquillityite was mined in a local billion-year-old rock formation, and according to the paleontologists who made the discovery, it may be more common on our planet than anyone could think. They also believe that the discovery proofs that similar chemical processes occur on the moon and on earth.

The habits and chemistry of earthly tranquillityite are consistent with the ones of its lunar counterpart. The mineral occurs in thin stripes in basaltic rocks, where it forms at a late crystallization stage. It is nearly opaque and dark red-brown in color.

Although tranquillityite is not a valuable gemstone, it is possibly one of the rarest minerals in our planet.

In 2014, a man proposed to his wife at the Burning Man event in the Black Rock Desert (Nevada, U.S.A.) with a custom 3D-printed ring which contained 0.32 gram of Tranquillityite. It was part of a lunar regolith that had fallen as a meteorite in Morocco, and one of the only samples not owned by NASA.

The Tranquillityite | Physical Properties

Chemical Composition: (Fe2+)8 Ti3 Zr2 Si3 O24
Cleavage: N.A.
Color: Gray, Dark Red-Brown
Crystal System: Hexagonal
Fracture: N.A.
Lustre: Submetalic
Mohs Hardness: N.A.
Specific Gravity: N.A.
Transparency: Opaque to Semitransparent

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