Serpentine, the stone most green tools are
If you own an inexpensive green stone tool, serpentine is the single most likely thing it is made from. It is a genuine and attractive material, softer and lighter than either jade, and it reaches the market under a set of names — “new jade”, “Korean jade”, “olive jade” — designed to be read as jade. Knowing its properties is the fastest way to place a green stone in the right bracket.
What serpentine is
Serpentine is not a mineral species but a group: a family of magnesium silicate hydroxide minerals with closely related compositions and different structures. The three principal members are antigorite, lizardite and chrysotile. The group forms by alteration of magnesium-rich igneous rock in the presence of water, which is a common geological process, and serpentine deposits are correspondingly widespread and inexpensive.
The rock made of these minerals is serpentinite, though in the trade “serpentine” covers both mineral and rock without much distinction. It occurs in green through yellow-green, olive, brown and near-black, frequently mottled or veined, and the mottled pattern of dark green on lighter green is the appearance the name refers to — it looks like snakeskin.
Bowenite is the name for a particularly compact, tough, translucent antigorite. It sits at the hard end of the group’s range and is the variety most easily mistaken for nephrite, having been used for carving in New Zealand and elsewhere for the same reasons.
Hardness, and why it matters here
Serpentine’s hardness spans roughly 2.5 to 5.5 across the group, with the softest members close to fingernail hardness and bowenite at the top of that range. Every relevant comparison follows from this: nephrite is about 6 to 6.5, jadeite about 6.5 to 7, quartz 7.
Being softer than steel, ordinary serpentine is scratched by a steel point. This makes it one of the few genuine positives available at home — the scratch test as an elimination works precisely because the hardness gap between serpentine and the jades straddles the hardness of common steel. A green stone that a knife point marks easily is not nephrite, not jadeite and not quartz, and serpentine is the most probable remaining candidate.
Specific gravity runs in the region of 2.4 to 2.8, which is lower than nephrite and appreciably lower than jadeite. A serpentine piece feels light for its size next to a jadeite one.
Lustre is typically waxy — soft rather than glassy, sometimes described as slightly soapy to the touch, which is the group’s most recognisable qualitative feature. Translucency ranges from opaque to usefully translucent in bowenite.
What softness means in an object
Serpentine’s low hardness has consequences that are visible on a used tool.
It scratches from ordinary handling. Grit on a surface, contact with another stone, a fingernail file in the same drawer: anything harder than about 3 will mark it, and everything is. A serpentine tool accumulates fine surface scratches, and its polish dulls.
It will not hold a crisp edge. A thin edge on a soft stone rounds and abrades. Where a nephrite edge stays defined, serpentine’s softens.
It is moderately tough for its hardness, but not tough like nephrite. Fine-grained serpentinite resists fracture reasonably well because it is an aggregate, and it is nonetheless a soft rock and will chip. Compact bowenite behaves considerably better than the softer members, which is why the two ends of the group’s range are worth separating rather than treating serpentine as one thing.
It takes dye readily. Being porous and often veined, it accepts colour easily, and pale serpentine dyed to a convincing green is one of the standard products of the low end of the trade.
What you can establish
WHAT YOU CAN TELL — a green stone that might be serpentine
· Steel point marks it easily → softer than 6;
not nephrite, jadeite or quartz
· Waxy lustre, faintly soapy feel → typical
· Mottled dark-on-light green veining → typical
· Light for its size → consistent; lower density
than either jade
· Colour pooled in the veining → dyed serpentine
· Which group member it is, or bowenite versus
soft antigorite → NOT DETERMINABLE at home.
Needs refractive index and spectroscopyA note on dust
One member of the group, chrysotile, is the fibrous form that is classified as asbestos, and serpentinite bodies can contain it. What follows from this is narrower than it sounds. The recognised concern in the literature is respirable dust generated by cutting, grinding and dry polishing — an occupational-hygiene issue in workshops, addressed with wet cutting and extraction. A finished, polished, solid object is not a dust source, and handling one is not the exposure route the hazard describes. This is stated because the fact belongs in an honest account of the material, not as advice of any kind, which is outside what this site does.
How it reaches you as jade
The names are the mechanism, and they follow the standard place-or-adjective plus gem name pattern almost perfectly. “New jade”, “Korean jade”, “Suzhou jade”, “olive jade”, “Teton jade”, “Styrian jade” — the qualifier is present, the material is serpentine, and the buyer reads the noun.
The commercial logic is straightforward. Serpentine is abundant, soft and therefore fast to carve, takes a good polish, and comes in exactly the green a buyer expects of jade. Nothing else available at the price does all four. A very large proportion of inexpensive green stone objects of every kind are serpentine, and this predates the current market by a long way.
The limit
You can establish that a green stone is soft, light and waxy, and those three findings together make serpentine much the most likely identification. You cannot confirm it. Distinguishing serpentine from nephrite at the hard end of the group’s range — bowenite against a mediocre nephrite — is genuinely difficult, and separating antigorite from lizardite requires instruments.
The useful conclusion is usually available anyway: a soft, light, waxy green stone is serpentine or something like it, whatever the listing said, and knowing you own a decent piece of serpentine is a complete answer to the question of what it is made of.