Lapis lazuli is a deep blue metamorphic rock, not a single mineral. Its blue comes from lazurite, and it usually contains white calcite and glittering gold-colored pyrite. The mines of Sar-e-Sang in Badakhshan, northeastern Afghanistan, have supplied lapis for thousands of years, reaching Egypt, Mesopotamia and later Europe. Ground lapis also gave artists ultramarine, the most expensive blue pigment of the Renaissance. Much lapis on the market today is dyed, reconstituted or imitated, so it pays to know the signs.
What lapis lazuli is
Lapis is a rock made of several minerals. The main ones are:
- Lazurite, a blue feldspathoid mineral in the sodalite group, which gives the color.
- Calcite, which forms white streaks and patches.
- Pyrite, a brassy iron sulfide that forms gold-colored flecks.
- Diopside, sodalite, hauyne and other minerals in smaller amounts.
The proportion of these minerals controls the look of a stone. Fine lapis is mostly lazurite with a little evenly spread pyrite. Lower grades have more calcite, which makes the blue look pale, patchy or grayish.
Lapis forms when limestone or marble is altered by heat and chemically active fluids during contact metamorphism, usually near intrusions of igneous rock. The page on metamorphic rocks and gemstones explains this process. Because lapis is a rock, its properties vary. The hardness is about 5 to 5.5, and the specific gravity ranges widely depending on how much pyrite and calcite it contains.
The name combines the Latin lapis, "stone," with a medieval Latin word for blue derived from the Persian lazhward. The same Persian root gave us the word "azure."
Sar-e-Sang and Afghan lapis
The Sar-e-Sang deposits sit high in the Kokcha River valley in Badakhshan. Lapis from this area appears in archaeological sites thousands of years old, and the region is generally considered one of the oldest continuously worked gem mining areas in the world. Miners historically broke the rock by heating it with fire and then dousing it with cold water, a method recorded by later travelers.
Marco Polo described the lapis mines of Badakhshan in his account of his travels in the late 13th century. Afghan lapis remains the standard for fine color: a deep, slightly violet-blue with small flecks of pyrite. Our page on the gems of Afghanistan covers the country's other gem deposits.
Lapis in the ancient world
Lapis traveled long distances very early. Craftworkers in Mesopotamia used it for beads, inlays and cylinder seals, and the Royal Tombs of Ur held a great deal of lapis, including in Queen Puabi's jewelry. The page on Mesopotamian jewelry describes these finds.
In Egypt, lapis was linked with the heavens and with royalty. It was set into collars, pectorals, scarabs and amulets, and Tutankhamun's funerary mask includes lapis inlays. Egyptians also made blue glass and faience partly to imitate lapis. Our page on ancient Egyptian jewelry covers these uses.
Other sources
- Chile produces lapis from the Andes, often lighter in tone and with more calcite. Chilean lapis is usually less costly than fine Afghan material.
- Russia has deposits near Lake Baikal in Siberia, which supplied lapis for Russian decorative work.
- Pakistan, Tajikistan and the United States (Colorado and California) also have smaller deposits.
Ultramarine pigment
For centuries, natural ultramarine was made by grinding lapis lazuli and extracting the blue lazurite. Simple grinding gives a dull grayish blue, because the calcite and other minerals dilute the color. Medieval painters used a process of kneading the powdered stone into a dough of wax, resin and oils, then working it in a mild lye solution so the blue particles separated out.
The name "ultramarine" comes from the Latin ultramarinus, "beyond the sea," because the stone came from Asia. The pigment was so costly that patrons sometimes specified in contracts how much ultramarine an artist should use, often for the robes of the Virgin Mary. Painters such as Giotto, Titian and Vermeer used it.
A French chemist, Jean-Baptiste Guimet, developed a synthetic ultramarine in the 1820s, and industrial production soon followed. Synthetic ultramarine is chemically similar and far cheaper, so natural lapis pigment became a specialty product.
Grading lapis
Lapis is judged mostly by color and composition:
- Color should be an intense, even, medium to dark blue, ideally slightly violet.
- Calcite should be minimal. White patches and streaks lower value.
- Pyrite should be in small, evenly spread flecks. Large patches or heavy concentrations lower value, though a little pyrite is often valued as proof of natural origin.
- Polish should be smooth and even.
Some buyers prefer a stone with no visible pyrite or calcite at all, a "pure" blue, which is rare.
Treatments and imitations
Dyeing and waxing
Pale or calcite-rich lapis is often dyed to improve its color, then waxed or oiled to seal the dye and improve the luster. Dyed lapis may show blue concentrated in cracks and around calcite. Gemologists sometimes test with a cotton swab and acetone, which can lift dye from the surface. Such tests can damage the stone, so leave them to a professional. The gemstone treatments page explains dyeing and disclosure.
Reconstituted lapis
Reconstituted lapis is made from lapis powder or small fragments bonded with plastic resin and pressed into blocks. It may also contain added dye or metallic flecks. It often has a uniform, artificial look, and under magnification you may see angular fragments set in a matrix.
Imitations
- Gilson created a lab-made imitation of lapis in the 1970s, sometimes called "Gilson lapis." It is more porous and lower in density than natural lapis.
- Dyed howlite, magnesite and jasper are sold as lapis. Jasper dyed blue, sold as "Swiss lapis" or "German lapis," shows uneven color and no pyrite.
- Sodalite is a related blue mineral that is often confused with lapis. It is usually more violet-blue, with white veins and little or no pyrite.
- Glass and plastic with metal flecks imitate lapis in cheap jewelry.
See how to identify gemstones for the tests that separate these.
Care
Lapis is about 5 to 5.5 on the Mohs scale, porous and sensitive to acids, heat and chemicals. Wear it carefully in rings and bracelets, and choose protective settings. Clean it with a soft, damp cloth and mild soap only. Avoid ultrasonic and steam cleaners, perfume, hairspray and household cleaners, which can dull the polish or remove dye and wax. The page on how to clean jewelry safely has more guidance.
Frequently asked questions
Is lapis lazuli a mineral?
No. Lapis lazuli is a rock made mostly of lazurite, with calcite, pyrite and other minerals mixed in.
What are the gold flecks in lapis?
The gold-colored flecks are pyrite, an iron sulfide mineral. Small, evenly spread flecks are a common feature of natural lapis.
Where does the best lapis come from?
Afghanistan, from the Sar-e-Sang area of Badakhshan, is the traditional source of the finest deep blue lapis.
How can you tell if lapis is dyed?
Look for blue concentrated in cracks or around white calcite, and color that comes off on a cloth. A gemologist can confirm dye safely.