What Is It Made Of

Nephrite, jadeite, and what jade means

“Jade” is not a mineral. It’s a name that gemmology applies to two entirely different minerals, and that the stone trade applies, with varying degrees of qualification, to at least a dozen more.

The two real ones aren’t closely related. They belong to different mineral groups, have different chemistry and different crystal structures, and were both called jade for the historical reason that they look similar and were used for similar purposes long before anyone could analyse them. When the distinction was finally made in the nineteenth century, both names were already too entrenched to displace.

So a tool sold as jade may be either of two legitimate minerals — or, quite often, a third thing entirely.

Nephrite

Nephrite is an amphibole, from the tremolite–actinolite series: a calcium-magnesium-iron silicate. The magnesium-rich end is paler and the iron-rich end greener and darker, which accounts for most of the colour range you see.

Its defining feature is structural rather than chemical. Nephrite is made of densely interlocking fibrous crystals — a felted mass rather than a set of discrete grains — and that microstructure makes it exceptionally tough. Not hard; tough. It resists fracturing to a degree that puts it among the toughest naturally occurring materials, which is precisely why it was used for tools and weapons for thousands of years before it was used for ornaments.

Its Mohs hardness sits around 6 to 6.5, which is below quartz. Specific gravity is roughly 2.90 to 3.03.

Historically, most Chinese jade artefacts are nephrite. It’s the jade of the long tradition, and sources include Central Asia, Siberia, New Zealand, British Columbia and elsewhere.

Jadeite

Jadeite is a pyroxene — a sodium aluminium silicate, chemically unrelated to nephrite despite the shared name.

Its structure is granular and interlocking rather than fibrous. Also very tough, though generally considered slightly less so than nephrite, and slightly harder at about 6.5 to 7 on Mohs. Specific gravity is higher, roughly 3.30 to 3.38, which is a meaningful difference — a jadeite piece feels distinctly heavier than a nephrite piece of the same size, and heavier still than most imitations.

Jadeite is the rarer of the two and includes the most valuable jade in existence. It arrived in China comparatively late, largely from Myanmar, and its finest grades occupy a price bracket that has nothing to do with the gua sha market.

What you can tell

WHAT YOU CAN TELL — is it nephrite, jadeite, or neither

  · Feels notably heavy for its size
                        → consistent with jadeite; not proof.
                          SG is measurable properly, and
                          "feels heavy" is not measuring it.

  · Waxy or oily lustre when polished
                        → typical of nephrite

  · Slightly granular, sometimes glassy lustre
                        → typical of jadeite

  · Very light for its size
                        → likely neither; consider serpentine
                          or a glass/resin imitation

  · Uniform, flawless, saturated colour throughout
    at a low price
                        → be suspicious; natural jade of
                          that quality is not cheap

  · Which of the two species it is
                        → NOT DETERMINABLE at home.
                          Requires refractive index, specific
                          gravity measurement, or spectroscopy.

That last row is the honest position and it applies to almost everything on this site.

The trade names

This is where most of the confusion lives, and it’s worth being precise about the mechanism: these names are usually not illegal. In many jurisdictions a qualified name — “new jade,” “Korean jade” — is a permitted trade description even when the material is not jade at all, provided the qualifier is present. The qualifier is exactly what a buyer skims past.

Common ones:

“New jade,” “Korean jade,” “Suzhou jade,” “olive jade” generally denote serpentine, a magnesium silicate that is not jade in any gemmological sense. Serpentine is much softer — the range runs from about 2.5 up to around 5.5 for the harder bowenite variety — and lighter, with a specific gravity in the region of 2.4 to 2.8. It’s an attractive, workable stone in its own right and a very large proportion of inexpensive green tools are made from it.

“Indian jade” usually means aventurine, a quartz containing platy mineral inclusions that produce a glittery shimmer. Quartz-family, Mohs 7, unrelated to jade.

“Australian jade” typically means chrysoprase, a green chalcedony — again quartz family.

“Amazon jade” may mean amazonite, a green variety of microcline feldspar, Mohs around 6 to 6.5.

“Mutton fat jade” is a genuine descriptor within the jade trade for a particular pale, dense nephrite — so this one is not a substitution name, and it gets applied loosely to things that aren’t.

The pattern: the word jade preceded by a place or an adjective is a warning, not a provenance. Actual nephrite and jadeite are usually described by species or by grade.

A, B and C

Within the jadeite trade there’s a standard classification that’s genuinely useful and worth knowing, because it distinguishes species from treatment:

Type A — natural jadeite, untreated apart from surface waxing, which is traditional and accepted.

Type B — jadeite that has been acid-bleached to remove staining and then impregnated with polymer to restore integrity and translucency. The mineral is real jadeite; its structure has been substantially altered, and it degrades over time as the polymer ages.

Type C — dyed. The colour is added.

Type B+C — both.

All four are jadeite. Only Type A is what most people mean when they say jade. Because the treatments are undisclosed at the low end of the market with some regularity, this classification is doing a lot of quiet work — how those treatments are performed is worth understanding, because each leaves traces.

Why the price range is so wide

A green flat stone can cost a few pounds or several hundred, and both can be described as jade without anyone lying, because:

  • One is serpentine sold as “new jade”; the other is nephrite.
  • One is dyed; the other isn’t.
  • One is Type B jadeite; the other is Type A.
  • One is reconstituted stone powder in resin; the other is a single piece.

None of which is visible in a photograph, and only some of which is determinable with the object in your hand.

The limit

Distinguishing nephrite from jadeite, or either from a good serpentine, is not something a non-specialist can do reliably. The properties that separate them — refractive index, precise specific gravity, spectroscopic signature — need instruments.

What you can do at home is rule some things out and notice when the story doesn’t hang together. A stone that’s light, warm, flawless and cheap is telling you something. Beyond that, a gemmologist with equipment is the only honest answer, and for most gua sha tools the cost of testing exceeds the cost of the tool — which is itself worth knowing before you spend an evening on it.

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