Is serpentine jade?
Serpentine is not jade to GIA: it is antigorite, lizardite or chrysotile, Mg3Si2O5(OH)4, hardness 2.5 to 3.5. New Zealand law differs: bowenite is pounamu.
No, not in gemmology. GIA defines jade as nephrite, jadeite and, under certain conditions, green omphacite; serpentine is none of them. Serpentine is a group name for three IMA species, antigorite, lizardite and chrysotile, which share one formula, Mg3Si2O5(OH)4, with hardness 2.5 to 3.5 on their sheets. New Zealand law is the exception: its 1997 pounamu act includes bowenite.
In short
- The criteria first: which rulebook? “Is serpentine jade” has three answers, depending on whose definition you use. The gemmological one (GIA) says no. The mineralogical one (the IMA list) says serpentine is not even a single species. The New Zealand legal one says bowenite, and some serpentine, is pounamu. The table sets out all three.
- GIA and the gem society. GIA calls jade a generic term for nephrite, jadeite and, under certain conditions, green omphacite. The International Gem Society says real jadeite and nephrite both have higher specific gravity and refractive index than serpentines, are much tougher, and that “Korean jade” is a misleading name for serpentine.
- The one-formula count. A script over the September 2026 IMA-CNMNC Master List finds no row for serpentine, bowenite or williamsite, and exactly three rows with the formula Mg3Si2O5(OH)4: antigorite, chrysotile and lizardite. Eight rows share the wider shape X3Si2O5(OH)4 or X2Si2O5(OH)4, kaolinite among them.
- The 13% water check. Worked on standard atomic weights, Mg3Si2O5(OH)4 is 43.63% MgO, 43.36% SiO2 and 13.00% water; the antigorite sheet prints an ideal column of 43.37, 43.63 and 13.00. Tremolite, the magnesium end of nephrite, is 2.22% water, and jadeite has none in its formula. The three are different kinds of silicate, not grades of one stone.
- The pounamu exception. Section 2 of New Zealand’s Ngai Tahu (Pounamu Vesting) Act 1997 defines pounamu as bowenite; nephrite, including semi-nephrite; and serpentine in its natural condition in land its Schedule describes. The gem society names a bowenite called tangiwai pounamu. The Act does not use the word jade.
| Material | IMA row? | Hardness | Density; 20.00 g piece in water | Jade to GIA? | Pounamu under the 1997 Act? |
|---|---|---|---|---|---|
| Jadeite, NaAlSi2O6 | Yes | 6 to 7 (sheet) | 3.34 (GIA); 14.01 g | Yes | Not named |
| Nephrite (tremolite–actinolite) | No; tremolite and actinolite have rows | 6.0 to 6.5 (GIA) | 2.95 (GIA); 13.22 g | Yes | Yes, including semi-nephrite |
| Antigorite, Mg3Si2O5(OH)4 | Yes | 2.5 to 3.5 (sheet) | 2.65 (sheet); 12.45 g | No | Only as serpentine in its natural condition in the Scheduled land |
| Bowenite (antigorite variety, IGS) | No | 4 to 6 (IGS) | 2.58 to 2.62 (IGS); 12.25 to 12.37 g | No | Yes, named as bowenite |
| Williamsite (antigorite variety, IGS) | No | 4.5 (IGS) | 2.6 to 2.62 (IGS); 12.31 to 12.37 g | No | Only as serpentine in the Scheduled land |
| Lizardite, Mg3Si2O5(OH)4 | Yes | 2.5 (sheet) | 2.55 (sheet); 12.16 g | No | Only as serpentine in the Scheduled land |
| Chrysotile, Mg3Si2O5(OH)4 (Handbook sheet: clinochrysotile) | Yes, as chrysotile; no row for clinochrysotile | 2.5 (sheet) | 2.53 (sheet); 12.09 g | No | Only as serpentine in the Scheduled land |
| “Korean jade” | No | As serpentine | As serpentine | No: IGS calls the name misleading | Not a term in the Act |
Is serpentine a jade? What GIA and the gem society say
Serpentine is not jade on GIA’s definition. GIA’s jade page reads: “Jade” is a generic term for nephrite, jadeite, and under certain conditions green omphacite. Serpentine is not in that list. The naming of jade itself, and the 30 misleading names Hobbs tabulated in 1982, are on is jade a mineral and are not repeated here.
The International Gem Society agrees, with numbers. Its serpentine article says natural serpentines can make convincing imitations, but that real jadeite and nephrite both have higher specific gravity and refractive index, are much tougher than any serpentine, and that gemmologists can usually tell them apart easily. It warns that some vendors sell serpentine under the misleading name “Korean jade”, and that serpentine is also used as the backing of a jadeite doublet, which is harder to identify once mounted.
Treated serpentine. The same article says serpentine may be impregnated with resin and dyed, and that green dye may enhance a jade-like look. Hobbs, in Gems & Gemology, records that positive proof of green dye in jadeite and serpentine can be found with the spectroscope. Dye in general is on how to tell if a crystal is dyed.
What is serpentine? Three species with one formula
The one-formula count: the September 2026 IMA list has no row for serpentine, and three rows that print exactly Mg3Si2O5(OH)4. They are antigorite (status Rd, 1998 s.p.), chrysotile (Rd, 2007 s.p., Poland) and lizardite (G, 1956, United Kingdom). The script also finds no row for bowenite, williamsite, serpentinite, clinochrysotile, orthochrysotile or parachrysotile. Widened to every row whose formula ends Si2O5(OH)4, it finds eight: antigorite, caryopilite, chrysotile, dickite, kaolinite, lizardite, nacrite and pecoraite.
The Handbook sheets put antigorite, lizardite and clinochrysotile in the kaolinite-serpentine group and call each polymorphous with the others. Antigorite: monoclinic, platy, bladed or fibrous, green, blue-green or white, hardness 2.5 to 3.5, density 2.65, named for Val Antigorio, Italy. Lizardite: fine-grained scales and massive aggregates, green, light yellow to white, hardness 2.5, density 2.55, named for its type locality, the Lizard complex, Cornwall; its sheet calls it probably the most common serpentine mineral. Clinochrysotile: asbestiform, fibrous along [100], hardness 2.5; the IMA list has a row for chrysotile but none for clinochrysotile.
The varieties. The International Gem Society calls serpentine a subgroup of the kaolinite-serpentine group, and bowenite and williamsite varieties of antigorite: bowenite at specific gravity 2.58 to 2.62 and hardness 4 to 6, williamsite at 2.6 to 2.62 and 4.5. Chrysotile is one of the six minerals named in the UK legal definition of asbestos quoted on is scolecite asbestos; the general page is toxic minerals in a collection. This is not health or safety advice.
Serpentine or jade in the hand: the 13% water check and the numbers
The 13% water check: serpentine’s formula is 13.00% water by mass, nephrite’s end member 2.22%, and jadeite’s none. On standard atomic weights Mg3Si2O5(OH)4 has a formula mass of 277.11 and is 43.63% MgO, 43.36% SiO2 and 13.00% H2O; the antigorite and clinochrysotile sheets print an ideal column of 43.37, 43.63 and 13.00. Tremolite, Ca2Mg5Si8O22(OH)2, is 2.22% water, and jadeite, NaAlSi2O6, has no hydrogen at all. That is a laboratory distinction, not a home test.
The numbers a collector can use. On the sheets, antigorite is hardness 2.5 to 3.5 and lizardite 2.5, against jadeite’s 6 to 7; GIA gives nephrite 6.0 to 6.5. At the sheet densities a 20.00 g piece reads 12.45 g in water as antigorite and 12.16 g as lizardite, against 13.22 g for nephrite and 14.01 g for jadeite at GIA’s figures. Hobbs gives serpentine a spot index of about 1.56, against about 1.66 for jadeite and 1.61 to 1.62 for nephrite. The full home sequence, and its 13.98 g line, is on how to tell if jade is real; the jadeite numbers are on jadeite.
The documented failure: bowenite. The gem society gives bowenite a hardness of 4 to 6, the hardest of the serpentines, so a scratch test can pass it as hard enough; the method and its damage are on how to test mineral hardness properly. Its weight, 12.25 to 12.37 g for 20.00 g, still sits well below nephrite’s 13.22 g, and Hobbs says bowenite’s specific gravity is normally lower than nephrite’s, which he puts at 2.90 to 3.00. Weigh it rather than scratch it; see how to measure specific gravity at home.
The pounamu exception: what New Zealand law says
One legal text groups serpentine with nephrite. Section 2 of New Zealand’s Ngai Tahu (Pounamu Vesting) Act 1997, read on legislation.govt.nz in its reprint as at 24 May 2013, says pounamu means— (a) bowenite: (b) nephrite, including semi-nephrite: (c) serpentine occurring in its natural condition in the land described in the Schedule. The Schedule describes areas marked A, B and C on survey office plans held in the Westland, Otago and Southland land districts.
What it does and does not say. The Act vests pounamu in Te Runanga o Ngai Tahu; it is a law of ownership, not of gemmology. It names bowenite outright, and serpentine only within the Scheduled land. It does not use the word jade, and it does not make serpentine nephrite. The International Gem Society illustrates a hei-tiki carved from a form of bowenite it calls tangiwai pounamu.
A documented conflict. Under GIA’s definition a bowenite carving is not jade; under the 1997 Act the same bowenite is pounamu, alongside nephrite. Both statements are correct within their own rulebook. A label that says pounamu tells you the New Zealand category; it does not tell you which mineral, and only a test does.
Who each answer is wrong for
“Serpentine is jade” is wrong for anyone using GIA’s definition, any gem laboratory report, and any label that names a mineral. A green carving reading near 12.1 to 12.5 g in water for 20.00 g is at serpentine weight, below nephrite and jadeite at GIA’s figures, whatever the label says.
“Serpentine is never jade” is too strong for New Zealand bowenite and Scheduled-land serpentine, which the 1997 Act classes as pounamu with nephrite. “Serpentine is a mineral” is wrong for everyone: on the IMA list it is three species, antigorite, lizardite and chrysotile, and a specimen label should name the one that was identified.
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