Lapis lazuli is a rock, not a mineral

Lapis lazuli is a metamorphic rock composed primarily of lazurite, the mineral that provides its blue color, along with varying amounts of white calcite and often small golden flecks of pyrite. Because it is a rock rather than a single crystal, quality varies not by clarity in the gemstone sense but by the proportion and evenness of lazurite versus calcite.

At roughly 5 to 6 on the Mohs scale it is a soft, opaque material, well below quartz and comparable to turquoise in its need for careful handling.

The finest lapis shows a deep, even, saturated royal blue with fine, evenly distributed pyrite flecks that read almost like stars, and minimal visible calcite. This grade has historically been associated with certain mining regions, though origin claims for any specific stone need a laboratory basis rather than assumption.

Lower grades show larger, paler patches of white or grey calcite running through the blue, and heavy calcite content is generally considered to reduce both the visual appeal and the value of the stone.

Because lapis is porous, lower-grade material is commonly stabilized with wax or resin to deepen color and fill surface porosity, and it is also frequently dyed blue to mask pale calcite patches and even out the tone. Both practices are long-standing in the trade but should be disclosed.

Dye can sometimes be detected by a cotton swab dampened with a little acetone showing color transfer at an inconspicuous spot, though this test carries some risk to the piece and is best left to a gemologist rather than attempted casually at home. A more reliable approach is simply asking the seller whether the material has been dyed or stabilized and expecting a clear answer.

Lapis is soft and somewhat porous, which makes it vulnerable to scratching from harder stones and to absorbing oils, perfume and household chemicals over time, sometimes leading to a gradual dulling of color.

We do not recommend ultrasonic or steam cleaning for lapis; the combination of porosity and calcite content makes it a poor candidate for either. A soft dry or barely damp cloth is the safest way to clean it, and lapis jewelry is best removed before swimming, bathing or applying lotion.

Lapis lazuli has one of the longest documented histories of ornamental use of any material, though specific historical dates and attributions are best left to specialist archaeological sources rather than a general jewelry guide. Within the periods we sell, it appears intermittently in Victorian jewelry and becomes considerably more common in mid-century and 1960s and 70s pieces, where its deep blue paired well with the era's bold use of gold and hard stone cabochons.

It is often found alongside turquoise, malachite and coral in mid-century designs that drew on a broader interest in colorful hard stones rather than any single revival movement.

Dyed jasper, dyed howlite and reconstituted lapis, made from crushed lapis and other material bound with resin, are the most common substitutes. Reconstituted material often shows an unnaturally uniform color and texture compared to natural lapis's more organic mottling and pyrite distribution.

Sodalite, a related blue mineral without lazurite or pyrite, is sometimes sold as or confused with lapis, but it typically lacks pyrite flecking and has a slightly different, more violet-leaning blue. A gemologist can confirm the material with simple density and reaction tests.