Two different minerals share the name, and a dozen cheaper stones borrow it. Density and toughness separate them.
Myanmar (jadeite), China, Canada, New Zealand, Guatemala (nephrite and jadeite)6 field tests
Jade is not one mineral. Two entirely separate minerals are called jade and have been for centuries: jadeite, a pyroxene, and nephrite, an amphibole. They are chemically unrelated, they come from different geology, and they differ in value by orders of magnitude — top imperial jadeite is among the most expensive materials on earth, while nephrite is a fine but comparatively modest stone.
Around those two sits a long list of green stones sold as jade with a qualifying word attached that quietly means 'not jade': serpentine as 'new jade' or 'Korean jade', aventurine as 'Indian jade', dyed quartzite as 'Malaysia jade', prehnite, and green glass. The qualifier is the tell, and in the trade it is well understood.
What all real jade shares, and what none of the substitutes have, is toughness. Both jadeite and nephrite are built from densely interlocked fibrous crystals, which makes them extraordinarily resistant to breaking — nephrite is arguably the toughest natural material there is. That is why jade was made into axes and adzes for thousands of years, and it is why a genuine piece rings rather than clacks.
Specific gravity does most of the work here, and it is measurable at home with a kitchen scale that reads to a tenth of a gram, a cup of water and a piece of thread. Weigh the piece dry, then weigh it suspended in water; the dry weight divided by the weight loss gives the specific gravity.
That single number separates jadeite from nephrite from serpentine, which no amount of looking will do reliably. It is also the check that exposes the commonest substitution, because serpentine is markedly lighter than either jade.
| Material | Specific gravity | Hardness | How it is sold |
|---|---|---|---|
| Jadeite | 3.30 – 3.38 | 6.5 – 7 | 'Type A' if untreated; the valuable jade |
| Nephrite | 2.90 – 3.03 | 6 – 6.5 | Canadian, Siberian, pounamu; honest and good |
| Serpentine | 2.44 – 2.62 | 2.5 – 5.5 | 'New jade', 'Korean jade', 'Olive jade' |
| Aventurine quartz | 2.64 – 2.69 | 7 | 'Indian jade' |
| Dyed quartzite | 2.6 – 2.7 | 7 | 'Malaysia jade' |
| Green glass | 2.4 – 2.6 | About 5.5 | Sold simply as jade, with bubbles inside |
Serpentine is the substitution to know. It is much softer in places — a knife will find a spot that marks — and its specific gravity is well below either true jade.
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 decisive test and it is genuinely easy. Weigh the piece dry. Then hang it from a thread so it is fully submerged in water without touching the sides or bottom, and weigh again. Divide the dry weight by the difference. Jadeite comes out at 3.30–3.38, nephrite at 2.90–3.03, serpentine at 2.44–2.62 and glass around 2.5. Nothing else you can do at home separates the three so cleanly.
A great deal of jadeite is bleached with acid and impregnated with polymer, then dyed — the trade calls this Type B and Type C, against untreated Type A. Under a loupe, dyed material shows green concentrated in a web following the stone's fracture network, with paler material between. That web pattern is the standard sign, and it is why untreated Type A jadeite commands the premium it does.
Genuine jade's interlocked fibrous structure gives it a distinctive resonant, high, slightly bell-like note when struck — a clear ring that carries. Serpentine, quartzite and glass produce a flatter, duller click. Jade dealers do this by suspending two beads on a thread and tapping them together, and once you have heard the difference it is hard to unhear.
On a polished jade surface, strong light at a low angle reveals a fine felted or fibrous texture, sometimes with a faint dimpling where harder and softer fibres took the polish differently. Jadeite often shows a granular 'orange peel' effect. Glass shows nothing but scratches and bubbles; dyed quartzite shows sugary crystalline grains.
Both jades are 6 or above and resist a steel blade. Serpentine ranges from 2.5 to 5.5 and almost always has somewhere a knife will mark, because it is variable within a single piece. A stone that takes a blade anywhere is not jade.
Jade is dense and conducts heat well, so it feels cool, smooth and surprisingly heavy, and stays cool for several seconds against the skin. Glass warms faster; plastic warms almost instantly and feels light. This is the oldest test in the Chinese trade and it is a reasonable first filter.
Jade's fraud problem has two quite separate halves and it helps to keep them apart. The first is substitution: a cheaper green stone sold as jade, usually with a geographic qualifier that a buyer is not expected to decode. The second is treatment of genuine jadeite, which is a much bigger business and much harder to see.
The treatment ladder is standardised in the trade. Type A is untreated jadeite — cut, polished, waxed at most — and it is the only kind that carries full value. Type B has been bleached in acid to remove brown staining and then impregnated with polymer to restore its integrity. Type C has been dyed. Type B+C has had both. A Type B piece can look better than a Type A piece and is worth a small fraction of it, and the polymer degrades and yellows over years.
For anything expensive, this is a laboratory question. Gemmological labs test jadeite as a matter of routine and issue a type designation, and on a four-figure purchase that certificate is the transaction, not an optional extra.
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.
| Material | What it typically fetches | What sets it |
|---|---|---|
| Serpentine sold honestly | $5 – 40 a carving | Not jade |
| Dyed quartzite 'Malaysia jade' | A few dollars | Not jade |
| Nephrite, good carving grade | $30 – 400 | Colour, translucency, workmanship |
| Jadeite, commercial Type A | $50 – 1,000 a cabochon | Colour and translucency |
| Jadeite, Type B or C | A small fraction of Type A | Treatment destroys the value |
| Fine imperial green jadeite | Five to seven figures | Translucency above colour |
Jade is the category in this room where a laboratory report changes the number most. On jadeite of any value, a type designation is the difference between the two ends of this table.
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.