The most heavily faked stone in the trade. Most of what is sold as turquoise is dyed howlite, reconstituted powder or plastic.
Iran, the American Southwest, China, Egypt, Mexico6 field tests
There is no material in this room with a worse honesty record than turquoise. Estimates from the trade have long put the proportion of turquoise on the market that is untreated natural stone in the single digits to low tens of percent, with the rest stabilised, reconstituted, dyed, or an entirely different mineral wearing the name.
That is not all fraud. Natural turquoise is porous and often too soft and chalky to cut, so stabilising it — impregnating it with clear resin under pressure — is a legitimate, near-universal and generally disclosed practice that makes usable stone out of unusable rough. The fraud is at the next two steps: reconstituted turquoise, which is powder and dust bound with resin into blocks, and simulant, which is a different mineral dyed blue.
The single most common simulant is howlite, a naturally white mineral with grey veining that takes blue dye beautifully and is soft enough that a knife cuts it. It is sold as turquoise constantly, and separating it takes about twenty seconds.
The honest way to describe this market is as a ladder, from stone that came out of the ground and was cut, down to plastic that never saw a mine. Each rung has a legitimate name and a price, and the fraud is almost always about which rung is being claimed.
The value gap is not marginal. Natural untreated high-grade turquoise from a named American mine can run hundreds of dollars a carat. Dyed howlite is a few dollars for a whole strand. Between those two sit stabilised and reconstituted material at very different prices, which is why the disclosure matters as much as the mineralogy.
| What it is | How it behaves | What it should cost |
|---|---|---|
| Natural, untreated turquoise | Hardness 5–6, waxy to dull lustre, may darken with skin oils over years | The premium — hundreds a carat for fine named-mine material |
| Stabilised turquoise | Genuine turquoise impregnated with clear resin; slightly plastic ring when tapped | A fraction of natural, and legitimate when disclosed |
| Reconstituted / 'block' turquoise | Turquoise powder bound in resin; uniform colour, suspiciously regular veining | Low — a manufactured composite, not a stone |
| Dyed howlite | Hardness 3.5 — a knife cuts it; dye concentrated in the grey veins | Pennies. A whole strand for a few dollars |
| Plastic or resin imitation | Warm to the touch, very light, a mould seam, melts under a hot pin | Nothing |
Stabilisation is normal and acceptable. Reconstituted material and dyed howlite sold as natural turquoise are not, and the price difference between the top and bottom of this table is three orders of magnitude.
Ordered by how much each one proves. The decisive tests are worth your first two minutes; the supporting ones only matter once those agree.
This is the check that eliminates the commonest fake in one stroke. Turquoise is 5–6 on the Mohs scale and a steel blade will not cut it cleanly. Howlite is 3.5 and cuts easily, leaving a white powder — and a white powder under a blue surface is the whole answer, because dyed howlite is white inside. Choose the drill hole of a bead or the back of a cabochon.
Under a 10× loupe, dyed howlite shows blue concentrated in and alongside its grey-brown veins, because the veins are more porous than the body and drank more dye — so the veins look darker blue than the matrix around them. Natural turquoise does the opposite: the mineral itself is blue and the veining is the host rock, which is brown, black or rust-coloured and not blue at all.
Heat a pin and touch it briefly to a hidden surface, such as the inside of a drill hole. Plastic and resin melt, deform and smell acridly of burning polymer. Reconstituted turquoise, being resin-bound, often gives the same smell. Natural and stabilised stone does not melt, though stabilised material may give a faint plastic note. Do this once, in a place nobody will see, and do not do it to a valuable piece.
Turquoise at 2.6–2.8 specific gravity feels like a stone. Plastic feels conspicuously light and warms to skin temperature almost immediately, where stone stays cool for several seconds. This is the check that catches the crudest imitations before you have taken anything out of the case.
Natural turquoise varies within a single stone and dramatically between stones — patchy, mottled, with the host rock intruding. A strand of beads all exactly the same shade of even blue, with regularly spaced webbing, is reconstituted block: it was made from a slab, so every bead came from the same homogeneous material. Uniformity across a whole piece of jewellery is a warning, not a sign of quality.
Some dyes lift onto a cotton bud dampened with acetone or nail-varnish remover, leaving blue on white cotton. A positive result is conclusive; a negative result proves little, since many dyes are fast and stabilising resin seals the surface. Test inside a drill hole or under a bezel.
The economics explain the market. High-grade natural turquoise from the classic American mines is genuinely scarce — several of the famous deposits are exhausted or closed — and demand for the look is enormous, particularly in silver jewellery. That combination guarantees substitution.
What the substitution buys is the appearance of the two things collectors pay for: a strong even blue, and attractive spiderweb veining. So the imitations are engineered to deliver exactly those, which is why they overshoot. Real turquoise is rarely as evenly blue or as neatly webbed as the fakes, because geology is untidy and a factory is not.
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 | $3 – 10 a strand | It is not turquoise |
| Reconstituted block | $1 – 5 a cabochon | A manufactured composite |
| Stabilised commercial turquoise | $1 – 20 a carat | Colour, webbing, cutting |
| Natural untreated, named mine | $20 – 300+ a carat | Mine, colour, hardness, webbing |
| High-grade Persian or Lander Blue | Four figures a carat at the top | Scarcity and closed deposits |
The spread from the top to the bottom of this table is roughly a thousandfold, which is exactly why the substitutions exist. Mine provenance carries as much weight here as it does in any category the house reads.
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.