A rock rather than a mineral: lazurite blue, calcite white and pyrite gold. The pyrite is the signature.
Badakhshan, Afghanistan — the same mines for six thousand years — with Chile and Siberia6 field tests
Lapis lazuli is a rock, not a mineral — an aggregate whose blue comes from lazurite, with white calcite and brassy flecks of pyrite mixed through it. That three-part composition is the identification, and it is why the finest lapis is described by what it lacks: little calcite, and pyrite present but finely distributed rather than in lumps.
The best material has come from the same valleys of Badakhshan in north-eastern Afghanistan for six thousand years. It was ground for ultramarine, the most expensive pigment in Renaissance painting, and the price of that pigment is a fair guide to how scarce good lapis has always been.
The imitations divide neatly. At the crude end, dyed howlite and dyed jasper — the same howlite that stands in for turquoise, dyed blue instead — and reconstituted lapis powder in resin. At the more careful end, synthetic spinel and glass with copper inclusions imitating pyrite, and the long-established Gilson product, which is a synthetic lapis rather than a stone.
Because lapis is an aggregate, its parts can be tested separately, and that is the most efficient way to work. The pyrite should behave like pyrite: metallic, brassy, hard, sitting in the stone rather than on it. The calcite should behave like calcite: white, soft, and it will fizz in acid. The blue should be lazurite: it should not come off on a swab.
An imitation almost always fails one of the three. Painted-on gold flecks sit proud of the surface or are flat and matte; dyed material bleeds; resin composites give no acid reaction anywhere and weigh too little.
| Component | What genuine lapis does | What an imitation does |
|---|---|---|
| Blue (lazurite) | Deep violet-blue, colour through the body | Dye pooled in fractures; lifts on an acetone swab |
| Gold flecks (pyrite) | Metallic, hard, embedded, irregularly shaped | Painted, flat, matte, sitting on the surface, or absent |
| White (calcite) | Effervesces in dilute acid; soft | Resin or plastic: no reaction |
| Hardness | 5 – 6 overall | Howlite 3.5 — a knife cuts it |
| Specific gravity | 2.7 – 2.9 | Resin composite well below; glass variable |
| Streak | Pale blue | Dyed howlite: white under the skin |
The pyrite is the single most useful component. It is hard to fake convincingly because it has to be metallic, hard and inside the stone.
Ordered by how much each one proves. The decisive tests are worth your first two minutes; the supporting ones only matter once those agree.
Genuine pyrite inclusions are metallic, brassy, hard, irregular in outline and continuous with the surrounding stone — polished flush with it, catching the light like metal. Painted or printed imitation flecks are flat and matte, sit slightly proud of or below the polished plane, and often repeat in size and spacing. Gold flecks that look like glitter are glitter.
Dyed howlite and dyed jasper commonly give up colour to a cotton bud dampened with acetone or nail-varnish remover — blue on white cotton is conclusive. Test inside a drill hole or under a bezel. A negative result is not proof of anything, because good dye jobs are sealed.
Lapis is 5–6 overall and resists a blade reasonably well. Dyed howlite at 3.5 cuts easily and produces white powder, which is the whole answer since howlite is white beneath its dye. Choose a surface nobody sees.
The white in genuine lapis is calcite, a carbonate, and it will effervesce faintly under acid where the blue lazurite will not. A resin composite gives no reaction anywhere. Watch under a hand lens for fine slow bubbles and wipe it dry immediately.
Fine lapis is expensive precisely because even, deep blue with little calcite and finely dispersed pyrite is rare. A large, evenly saturated, calcite-free piece at a modest price is a manufactured product — either Gilson synthetic lapis or a dyed composite. Real high-grade lapis costs what it costs.
Reconstituted lapis — powder bound in resin — looks slightly granular and homogeneous under magnification, without the patchy, veined, three-component structure of the rock. It also weighs noticeably less than solid stone and may smell of polymer under a briefly heated pin.
Lapis has been imitated since antiquity, and the modern versions are the same idea with better materials. The base rate matters: good lapis is genuinely scarce and priced accordingly, so cheap deep-blue material with tidy gold flecks should be assumed to be manufactured until it proves otherwise.
There is one legitimate synthetic worth naming. Gilson lapis is a manufactured product that reproduces lapis's appearance including pyrite-like inclusions, and it has been sold honestly under its own name for decades. It is a synthetic, not a fake, and it should be priced as one.
Each of these is checked differently. The ones with their own page have enough that is specific to them to be worth reading separately.
Specimen figures rather than gem figures, for material in honest condition. Most finds are worth very little, and saying so plainly is more useful than encouraging you.
| Grade | What it typically fetches | What sets it |
|---|---|---|
| Dyed howlite or jasper | A few dollars a strand | Not lapis |
| Reconstituted lapis composite | $5 – 20 | A resin composite |
| Commercial lapis, calcitic | $5 – 30 a cabochon | Pale, mottled, heavy white veining |
| Good Afghan lapis | $50 – 300 a cabochon | Deep even blue, little calcite |
| Top-grade Afghan, fine pyrite | Priced by the gram | Colour depth above all |
Lapis grades on the absence of calcite far more than on the presence of anything. Finely dispersed pyrite is a positive; coarse pyrite lumps and white veining are not.
Lovenhall StoneThe tests tell you what it is. The instrument reads a photograph and offers a name to start from — then hands you back to the tile and the coin, which are what settle it.