The gem known as lapis lazuli, or simply lapis, is actually a rock, composed of lazurite, hauyne. sodalite, and nosean, all members of the sodalite group of minerals. Lazurite itself may be considered a sulfurrich hauyne. Calcite and pyrite in various percentages are also present in the rock. The finest lapis is considered to be a solid, deep blue with no white calcite spots and just a sprinkling of brassy yellow pyrite. Such material is found only in Afghanistan and Pakistan, in commercially interesting quantities. The Colorado material is quite fine but of limited availability
Lapis Lazuli Value
The International Gem Society (IGS) has a list of businesses offering gemstone appraisal services.
Lapis Lazuli Information
|Is a Variety of||Lazurite|
|Crystallography||Isometric; Crystals very rare, dodecahedral, up to about 2 inches in size. Also massive, compact, disseminated, in veins.|
|Refractive Index||1.50 - 1.55|
|Hardness||5-6 (depending on impurity content).|
|Density||Pure: 2.38-2.45. gem lapis: 2.7-2.9 or higher if much pyrite present.|
|Cleavage||Imperfect; none in massive material. Fracture uneven.|
|Stone Sizes||Rough blocks from Afghanistan, of fine color, are known up to 100 kg. One block of Chilean material, found in a Peruvian grave, was 24 x 12 x 8 inches. A 40.5 cm tall vase of fine blue material is in the Pitti Palace, Florence, Italy.|
|Luminescence||Orange spots or streaks in LW (Afghanistan and Chile), dimmer and more pink in SW. X-rays cause yellowish glow in streaks. May fluoresce whitish in SW,|
|Special Care Instructions||Avoid contact with chemicals|
STREAK: Light blue.
CHEMICAL TEST: A drop of HCI on lapis releases H2S gas (rotten egg odor).
OCCURRENCE: Contact metamorphic mineral in limestone, formed by recrystallization of impurities; also in granites.
Italy: Labrador: Mogok. Burma: Pakistan. California: blue-gray with white spots.
Colorado: stringers in limestone, dark color. much pyrite, from Italian Mountain in the western part of the state.
Badakshan, Afghanistan: among the oldest operating mines in the world (7,000 years). Lapis occurs in large blocks and crystals in white matrix. Source of the world’s finest lapis.
Studyanka River, Mongolia: light blue lapis, with pyrite.
Chilean Andes: gray and blue mixture, color inferior to Afghan material.
COMMENTS: The gem known as lapis lazuli, or simply lapis, is actually a rock, composed of lazurite, hauyne. sodalite, and nosean, all members of the sodalite group of minerals. Lazurite itself may be considered a sulfurrich hauyne. Calcite and pyrite in various percentages are also present in the rock. The finest lapis is considered to be a solid, deep blue with no white calcite spots and just a sprinkling of brassy yellow pyrite. Such material is found only in Afghanistan and Pakistan, in commercially interesting quantities. The Colorado material is quite fine but of limited availability
Lapis is very well suited to men’s jewelry because it has a rich blue color and does not show wear easily. It is fairly tough, takes an excellent polish, and is dark enough not to be a problem in color coordination with clothes.
Used since ancient times, (some estimates say as early as 6000 BCE), it is still a popular choice today. Beads, jewelry, and carvings have been found in numerous archeological sites from that time onward, indicating a spread in use from Afghanistan, throughout the Middle East and Egypt, to Asia, and the Roman World.
The name “lapis lazuli” comes from the Persian “lazhward”, and literally means “blue stone”. Throughout the Latin speaking Roman World, however, the word “sapphirus” was used (with the same meaning), and has lead to speculation that in certain historical sources, the “sapphires” of antiquity were really lapis. The Egyptians long valued this stone, not only as a source of carving and inlay material, but also in ground form as a cosmetic. If you’ve ever wondered who to blame for bright blue eyeshadow.
Painters from pre-Renaissance times until the Modern Era used ground lapis as their pigment “ultramarine”, and that old formula is still used today by museum conservators (and forgers!)
Jewelry uses predominate today and most commonly this gem is set in silver in modestly priced jewelry pieces. There is a growing trend, however, to emulate the jewelers of earlier times, and to set fine quality stones in gold, with diamonds or colored gems.
NAME From a Persian word, lazhward, meaning blue.
|Multi-gem intarsia with lapis border and frame|
Lapis has always been a gem of choice for inlays, insets and intarsias. How could any gem artist resist the contrast and eye appeal of its bright blue color?
The colors of lapis range from a medium grayish blue, to intense royal blue, to deep indigo, with varying amounts of white and brassy gold from calcite and pyrite, respectively. Some purists desire a gem that is almost entirely lazurite, in a deep uniform blue, but most seek a piece with a moderate to generous sprinkling of golden pyrite. Pliny the Elder, in his famed ancient treatise on all things Natural, called lapis “a fragment of the starry firmament” in admiration of the deep blue with twinkling bits of gold.
Although they don’t agree as to how much pyrite is ideal, most all admirers and collectors of fine lapis, agree that, the less calcite, the better. Calcite can be seen as streaks or patches within the darker blue, or it can predominate in the mix giving the rock an overall lighter blue shade. The popularity of denim/country-western clothing has given marketers a niche for what once was considered low quality, virtually unsalable material from Chile. Cleverly dubbed “denim lapis” it is sold widely on home shopping channels, at swapmeets, and through direct mail catalogues.
Perhaps it is this gem’s long history, or its ethereal color scheme that make such it a significant stone amongst those who ascribe mystical, spiritual or healing properties to gemstones. It is an alternate birthstone for September in the European/American system, and has prominent positions in other systems as well.
Synthetics and Simulants
Lapis lazuli has been successfully synthesized by Gilson in France and Chatham in the USA. Many of the large jewelry supply houses offer the synthetic version either with, or without, pyrite. Although the synthetics are a modern invention, lapis simulants go back at least as far as early Egyptian times. Artifacts using glass backed with blue paint, and blue ceramic materials in lieu of lapis, include the famed King Tut Death Mask. Such items attest to the Ancients love of this dark blue gem, and the ingenuity they used to simulate it when the natural material was scarce or too costly.
Modern era simulants include enamel, glass, plastic, and a variety of dyed gems such as howlite and jasper, (aka “Swiss lapis”). The only natural gemstone readily available in large enough sizes, and in a deep enough blue to be a convincing lapis simulant is sodalite.
Although this gem’s hardness of 5-6 suggests that some degree of care is needed in setting and wearing, it is still widely used in rings and bracelets. It would be wise to choose a protective setting for these uses, or limit wear to less than 24/7. Even given protective care, a well worn ring or bracelet gem may need repolishing periodically. Pendants, earrings, brooches and tie or lapel pins can be worn daily with little worry.
Steam, chemical solvents, and ultrasonics should be avoided for cleaning. The old standby of a soft brush and mild soap would be safest.
Value in lapis is determined almost exclusively by color, with deep, intense, blue with violet tones being at the apex. Fine grained, uniform specimens attain a smooth highly polished surface not seen in lower grades. Calcite inclusions always lower the value, but pyrite inclusions enhance it in the minds of many collectors and jewelry lovers. The quality of polish, and the artistry of fashioning are also factors in value.
by Dr. Joel Arem; Barbara Smigel (from Artistic Colored Stones)