Turquoise is the stone where the word "natural" is doing the most work and meaning the least. In the bead trade, a strand described as turquoise can be untreated stone, resin-stabilised stone, dyed howlite, pressed blocks of turquoise dust, or plastic. All five look blue in a photograph.
None of that makes turquoise a bad buy. It makes it a stone you have to read properly.
What turquoise is, in mineral terms
A hydrated copper aluminium phosphate. The blue comes from copper, the green from iron substituting for some of that copper. Hardness is only 5 to 6 on the Mohs scale, and porous material can be softer still — which is exactly why the trade stabilises it.
Turquoise almost always forms with a host rock attached. Those brown, black or sandy lines running through the stone are called matrix, and they are the host rock — limonite, ironstone, chert — not a flaw. Matrix is one of the most useful diagnostic features you have.
The four things sold as turquoise
Natural, untreated. Stone with enough density to polish without help. Rarer than the market implies, and priced accordingly. It will darken slightly with skin oils over years, which most buyers consider desirable.
Stabilised. Impregnated with resin under vacuum to fill porosity and lock colour. This is standard practice, it is legal, and most wearable turquoise at accessible prices is stabilised. It does not make the stone fake.
Dyed howlite or magnesite. White porous minerals dyed blue. These have black or grey veining that looks drawn rather than geological, and the dye often pools darker in the veins.
Block or reconstituted. Turquoise dust and resin pressed into blocks and cut into beads. Sometimes called "block turquoise". It contains real turquoise, but it is a manufactured product.
How to tell them apart
Matrix should look geological. Natural matrix varies in width, wanders, branches, and has its own texture. Dyed howlite veins tend to be thin, uniformly dark and oddly regular. If the veins look like ink drawn into a crack, they probably are.
Colour should not be in the cracks. Look at a bead with a magnifier. Dye concentrates in fractures and around the bead hole. Natural turquoise colour is in the body of the stone.
Wipe test. A damp white cloth rubbed on a dyed bead may pick up blue. Natural and stabilised stone will not transfer colour, though stabilised material can feel slightly waxy.
Weight and temperature. Plastic imitations feel light and warm up fast. Block material is heavier than plastic but lacks the fine grain of stone.
Ask directly. A seller who deals in turquoise will tell you natural, stabilised or block in one sentence. If the answer is evasive, that is the answer.
What to look for when you buy
Colour. Sky blue through to blue-green is the natural range. A very saturated, uniform "pool blue" across every bead is more typical of treated or block material than of natural stone.
Matrix character. Spiderweb matrix — fine dark webbing on bright blue — is prized and expensive. Heavy brown matrix is less valuable but often more durable and more interesting.
Consistency. Beads are sorted for colour before stringing. A strand with obvious light and dark patches was not sorted, which usually reflects a lower price point.
Bead edges. At Mohs 5 to 6, turquoise abrades at bead holes. Check for chalky white edges, which suggest soft, heavily treated material.
Care and wear
Turquoise is porous and hates chemistry. Keep it away from perfume, hairspray, sunscreen, chlorine and soap. Do not soak it, and never use ultrasonic or steam — untreated and stabilised stone can both be damaged.
Wipe with a soft dry cloth after wearing. Store away from direct sun, since some dyed and treated material fades. If your turquoise darkens over years, that is skin oil and is considered normal patina. Full method in the crystal care guide.
What the meaning claims can and cannot support
Turquoise has one of the longest protective traditions of any stone, from Persian and Native American use to Tibetan and Egyptian jewellery. Those associations are cultural history and worth respecting. They are not evidence of a physical effect, and there is no clinical support for claims about protection or healing.
What you can actually judge is honesty about treatment. A well-chosen stabilised turquoise bracelet at a stabilised price is a good purchase. An untreated stone sold as natural when it is dyed howlite is not, at any price. Our buying guide covers how to ask.
Frequently asked questions
Is stabilised turquoise real turquoise? Yes. It is genuine stone impregnated with resin to reduce porosity. It should be disclosed and priced below untreated material.
How can I tell turquoise from dyed howlite? Howlite veins are thin, dark and regular, and dye collects in cracks and around bead holes. Natural matrix varies in width and texture.
What is turquoise's hardness? 5 to 6 on the Mohs scale, and porous material can be softer. It scratches and abrades more easily than quartz.
Does turquoise change colour? Untreated stone darkens gradually from skin oils, which most people like. Dyes and some treatments can fade in sunlight.
Can I wear turquoise in water? Better not. It is porous, and chlorine, soap and hot water can dull the polish and affect treated colour.
See the current turquoise bracelets, or compare it with lapis lazuli and agate.