Lapis Lazuli



Introduction. Lapis lazuli is one of the oldest of all gems, with a history stretching back some 7000 years or more. This mineral is important not just as a gem, but also as a pigment, for ultramarine is produced from crushed lapis lazuli (this is why old paintings using ultramarine for their blue pigments never fade).

Color. For lapis lazuli, the finest color will be an even, intense blue, lightly dusted with small flecks of golden pyrite. There should be no white calcite veins visible to the naked eye and the pyrite should be small in size. This is because the inclusion of pyrite often produces discoloration at the edges which is not so attractive. Stones which contain too much calcite or pyrite are not as valuable.

Clarity. Lapis lazuli is essentially opaque to the naked eye. However, fine stones should possess no cracks which might lower durability.

Cut. Lapis lazuli is cut similar to other ornamental stones. Cabochons are common, as are flat polished slabs and beads. Carvings and figurines are also common.

Prices. Lapis lazuli is not an expensive stone, but truly fine material is still rare. Lower grades may sell for less than $1 per carat, while the superfine material may reach $100–150/ct. or more at retail.

Stone Sizes. Lapis lazuli may occur in multi-kilogram sized pieces, but top-grade lapis of even 10–20 carats cut is rare.

Name. The name lapis means stone. Lazuli is derived from the Persian lazhward, meaningblue. This is also the root of our word, azure.

Sources. The original locality for lapis lazuli is the Sar-e-Sang deposit in Afghanistan’s remote Badakhshan district. This mine is one of the oldest in the world, producing continuously for over 7000 years. While other deposits of lapis are known, none are of importance when compared with Afghanistan. Lapis lazuli is also found in Chile, where the material is heavily mottled with calcite. Small amounts are also mined in Colorado, near Lake Baikal in Siberia, and in Burma’s Mogok Stone Tract.

Enhancements. The most common enhancement for lapis lazuli is dying (staining), where a stone with white calcite inclusions is stained blue to improve the color. Other enhancements commonly seen are waxing and resin impregnations, again, to improve color. The color of stained lapis is unstable and will fade with time. As with all precious stones, it is a good practice to have any major purchases tested by a reputable gem lab, such as the GIA orAGTA, to determine if a gem is enhanced.

Imitations. Sintered synthetic blue spinel was once used as an imitation of lapis lazuli, but is rarely seen today. So-called synthetic lapis lazuli (such as the Gilson product) is more properly termed an imitation, since it does not match exactly the structure and properties of the natural. It is found in various forms, complete with pyrite specks (but all lacking calcite). Various forms of glass and plastic are also commonly seen as lapis imitations.


Properties of Lapis Lazuli


CompositionRock made primarily of lazurite (Na, Ca)8(Al, Si)12O24(S, SO4). Also contains haüyne, sodalite and nosean, which are all members of the sodalite group.


Hardness (Mohs)


Variable. Generally 5–6


Specific Gravity


Variable. Generally 2.7–2.9


Refractive Index


ca. 1.50


Crystal System


None (lapis is a rock). Lazurite, the main constituent, is isometric, and frequently occurs as dodecahedra.


Colors


Blue, mottled with white calcite and brassy pyrite


Pleochroism


None


Phenomena


None


Handling


Due to its softness, care must be taken in the wearing of lapis lazuli.


Enhancements


Frequently dyed or impregnated


Synthetic available?


Yes



Lapis lazuli is a gemstone of the kind that might have come straight out of the Arabian Nights: a deep blue with golden inclusions of pyrites which shimmer like little stars.
This opaque, deep blue gemstone has a grand past. It was among the first gemstones to be worn as jewellery and worked on. At excavations in the ancient centres of culture around the Mediterranean, archaeologists have again and again found among the grave furnishings decorative chains and figures made of lapis lazuli – clear indications that the deep blue stone was already popular thousands of years ago among the people of Mesopotamia, Egypt, Persia, Greece and Rome. It is said that the legendary city of Ur on the Euphrates plied a keen lapis lazuli trade as long ago as the fourth millennium B.C., the material coming to the land of the two great rivers from the famous deposits in Afghanistan. In other cultures, lapis lazuli was regarded as a holy stone. Particularly in the Middle East, it was thought to have magical powers. Countless signet rings, scarabs and figures were wrought from the blue stone which Alexander the Great brought to Europe. There, the colour was referred to as 'ultramarine', which means something like 'from beyond the sea'.
The most expensive blue of all time
The euphonious name is composed from 'lapis', the Latin word for stone, and 'azula', which comes from the Arabic and means blue. All right, so it's a blue gemstone - but what an incredible blue! The worth of this stone to the world of art is immeasurable, for the ultramarine of the Old Masters is nothing other than genuine lapis lazuli. Ground up into a powder and stirred up together with binding-agents, the marble-like gemstone can be used to manufacture radiant blue watercolours, tempera or oil-paints. Before the year 1834, when it became possible to produce this colour synthetically, the only ultramarine available was that valuable substance made from genuine lapis lazuli that shines out at us from many works of art today. Many pictures of the Madonna, for example, were created using this paint. But in those days, ultramarine blue was not only precious and so intense that its radiance outshone all other colours; it was also very expensive. But unlike all other blue pigments, which tend to pale in the light, it has lost none of its radiance to this very day. Nowadays, the blue pigment obtained from lapis lazuli is mainly used in restoration work and by collectors of historical paints.
The stone of friendship and truth
Lapis lazuli is regarded by many people around the world as the stone of friendship and truth. The blue stone is said to encourage harmony in relationships and help its wearer to be authentic and give his or her opinion openly.
Lapis lazuli is an opaque rock that mainly consists of diopside and lazurite. It came into being millions of years ago during the metamorphosis of lime to marble. Uncut, lapis lazuli is matt and of a deep, dark blue colour, often with golden inclusions and whitish marble veins. The small inclusions with their golden shimmer, which give the stone the magic of a starry sky, are not of gold as people used to think, but of pyrites. Their cause is iron. The blue colour comes from the sulphur content of the lazurite and may range from pure ultramarine to a lighter blue. At between 5 and 6 on the Mohs scale, this stone is among the less hard gemstones.
Lapis lazuli is a versatile and popular gemstone which has shown extraordinary stability in the turbulent tides of fashion. No wonder, since it has fascinated both men and women for thousands of years with its fabulous colour and those golden points of light formed by pyrites.

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