Is lapis lazuli a mineral or a rock?
Lapis lazuli is a rock: GIA calls it an aggregate of lazurite, calcite and pyrite. Lazurite is the mineral, hardness 5 to 5.5, redefined by the IMA in 2021.
Lapis lazuli is a rock, not a mineral. GIA calls it an aggregate of several minerals, mainly lazurite, calcite and pyrite. Lazurite is the mineral that makes it blue: hardness 5 to 5.5, density 2.38 to 2.45, with its own row on the IMA list, redefined in 2021. Lapis lazuli itself has no IMA row.
In short
- Lapis is a rock because it is a mixture. GIA calls it an aggregate of several minerals, mainly lazurite, calcite and pyrite, with lesser diopside, amphibole, feldspar or mica. The International Gem Society calls it a rock composed of lazurite, haüyne, sodalite and nosean, all sodalite-group minerals. A mineral, by definition, is homogeneous; lapis is not.
- Seven of the ten names have IMA rows. Of the 10 mineral names the two sources give, a script over the September 2026 IMA list finds rows for 7: lazurite, calcite, pyrite, diopside, haüyne, sodalite and nosean. Amphibole, feldspar and mica are group names with no row, and lapis lazuli has none.
- Lazurite was redefined in 2021. The IMA list gives Na7Ca(Al6Si6O24)(SO4)(S3)−·H2O, status Rd, 2021 s.p. The Handbook sheet, older, gives Na6Ca2Al6Si6O24[(SO4),S,Cl,(OH)]2: hardness 5 to 5.5, density 2.38 to 2.45, streak bright blue.
- The 2.71 ceiling: lazurite and calcite alone cannot weigh more than calcite. Calcite is 2.7102 and lazurite 2.38 to 2.45, so any mix of the two sits at or below 2.71. GIA's 2.75 ± 0.25 runs above that, which needs a denser mineral: pyrite at 5.018 or diopside at 3.22 to 3.38. In a lazurite and pyrite mix, 2.75 takes 11.7 to 14.0% pyrite by volume.
- Imitations are named, and the decisive tests are for professionals. The IGS lists enamel, glass, plastic, dyed howlite and dyed jasper sold as Swiss lapis, calls sodalite the only convincing natural simulant, and records synthetic lapis by Pierre Gilson. It says acid and streak tests are destructive and for a professional gemmologist only.
| Name | Named by | IMA row: status, year | Hardness (Handbook) | Density (Handbook) | Streak (Handbook) | Role in lapis |
|---|---|---|---|---|---|---|
| Lazurite | GIA, IGS | Rd, 2021 s.p. | 5 to 5.5 | 2.38 to 2.45 | Bright blue | The blue (GIA) |
| Calcite | GIA | G, 1836 | 3 | 2.7102 | White | White streaks and patches (IGS) |
| Pyrite | GIA | G, no year | 6 to 6.5 | 5.018 | Greenish black to brownish black | Golden flecks (GIA) |
| Diopside | GIA, lesser | A, 1988 s.p. | 5.5 to 6.5 | 3.22 to 3.38 | White, gray, gray-green | Minor |
| Haüyne | IGS | G, 1807 | 5.5 to 6 | 2.44 to 2.50 | Slightly bluish to colourless | Sodalite group |
| Sodalite | IGS | G, 1811 | 5.5 to 6 | 2.27 to 2.33 | White | Sodalite group; also the natural simulant (IGS) |
| Nosean | IGS | G, 1815 | 5.5 | 2.30 to 2.40 | Not printed | Sodalite group |
| Amphibole, feldspar, mica | GIA, lesser | No row: group names | Not one sheet | Not one sheet | Not one sheet | Minor |
| Lapis lazuli, the rock | GIA, IGS | No row | IGS: 5 to 6 | GIA: 2.75 ± 0.25 | IGS: light blue | The rock itself |
Is lapis lazuli a mineral or a rock?
Lapis lazuli is a rock: a mixture of minerals, of which lazurite supplies the blue. The GIA lapis lazuli page calls it an aggregate of several minerals and names the three major ones as lazurite, calcite and pyrite, with lesser amounts of diopside, amphibole, feldspar or mica. Its facts panel gives the mineral as rock and the chemical composition as an aggregate.
Why the distinction is real. Tropper's textbook definition, quoted on crystal vs mineral, requires a mineral to be a homogeneous solid. A piece of lapis has white calcite, brassy pyrite and blue lazurite in one stone, each with its own hardness and density, so no single set of properties describes it. Lazurite does have one: the Handbook of Mineralogy lazurite sheet gives cubic crystals, dodecahedra to 5 cm, and calls it a contact metamorphic mineral in limestones.
What mineral is lapis lazuli made of? Lazurite, and the IMA list
Lazurite is the IMA mineral name; lapis lazuli is the rock name. The September 2026 IMA list gives lazurite as Na7Ca(Al6Si6O24)(SO4)(S3)−·H2O, status Rd, redefined, 2021 s.p., with Afghanistan / Russia in the country column. The Handbook sheet, older, writes Na6Ca2Al6Si6O24[(SO4),S,Cl,(OH)]2 and places it in the sodalite group. Both are shown because they differ.
The name count, by script: GIA and the IGS between them name 10 minerals in lapis. Seven have IMA rows: lazurite, calcite, pyrite, diopside, haüyne, sodalite and nosean. Amphibole, feldspar and mica are group names, which an exact-name search of the list does not find. Neither lapis nor lapis lazuli is a row. The IGS adds that lazurite itself may be considered a sulphur-rich haüyne.
Where the sheet places it. The Distribution field names exceptional crystals from Sar-e-Sang, Badakhshan Province, Afghanistan; the Slyudyanka and Bystraya basins near Lake Baikal, Russia; the Pamir, Tajikistan; Monte Somma and the Alban Hills, Italy; and the Cazadero River near Ovalle, Chile. The name, says the sheet, is from the Persian lazhward, for blue.
Why lapis is heavier than lazurite: the 2.71 ceiling
The 2.71 ceiling: a rock of lazurite and calcite alone cannot exceed calcite's density, 2.7102. Lazurite is 2.38 to 2.45 on its sheet, so every mix of the two lands between its figure and calcite's. GIA gives lapis a specific gravity of 2.75 ± 0.25, and the IGS 2.7 to 2.9 for gem lapis, higher if much pyrite is present. Readings above 2.71 therefore need a denser mineral, and GIA's list supplies two: pyrite at 5.018 and diopside at 3.22 to 3.38.
Worked, as a two-mineral mix of lazurite and pyrite, with density = sum of volume fraction × density: reaching 2.75 takes 11.7 to 14.0% pyrite by volume, and reaching 3.00 takes 21.4 to 23.5%. At 3.00 that pyrite is 35.8 to 39.3% of the mass. Real lapis has calcite and other minerals too, so these are bounds for a model, not an analysis of any stone.
On a scale: a 20.00 g piece reads 12.00 to 13.33 g in water across GIA's range, and 11.60 to 11.84 g as pure lazurite. The method is on how to measure specific gravity at home. Pyrite itself is on how to tell if pyrite is real.
Is my lapis lazuli real? Imitations and simulants
The International Gem Society lapis lazuli article lists the imitations: enamel, glass, plastic, and dyed gems such as howlite and jasper, the latter misleadingly sold as Swiss lapis. It calls sodalite the only natural gemstone readily available in large enough sizes, with a deep enough blue, to be a convincing simulant. It also records synthetic lapis made by Pierre Gilson in France and Carroll Chatham in the United States, and lists dyeing as a common treatment.
Sodalite is lighter than lapis on its sheet. The Handbook sodalite sheet gives density 2.27 to 2.33 and a white streak, against lazurite's 2.38 to 2.45 and bright blue streak. A 20.00 g sodalite piece reads 11.19 to 11.42 g in water. The IGS says streak and acid tests on lapis are destructive and should be done only by a professional gemmologist, so this page does not offer them as home tests. Dye checks in general are on how to tell if a crystal is dyed.
More definitions are in the collecting guides. Nothing on this site is offered for sale; the wanted list is the only commercial route.