How to tell if jade is real
Real jade is jadeite (SG 3.34) or nephrite (2.95); over 13.98 g in water for 20 g fits jadeite. Quartz and prehnite pass touch and scratch; calcite, touch.
To tell if jade is real, use a scale and a refractometer, not folk tests. Jadeite gives a spot reading near 1.66 and specific gravity 3.34; nephrite 1.61 to 1.62 and 2.95. A 20.00 g jadeite piece weighs about 14.01 g in water, nephrite 13.22 g. Touch, scratch and flashlight tests each pass some fakes; treatment needs a laboratory.
In short
- Real jade is two materials. GIA calls jade a generic term for nephrite, jadeite and, under certain conditions, green omphacite. Each has its own numbers, so “is it real” means “is it jadeite or nephrite, and is it treated”. The naming is on is jade a mineral.
- The 13.98 g line. Hobbs (Gems & Gemology, 1982) separated jadeite with a 3.32 heavy liquid: jadeite stays suspended or sinks, nephrite and most simulants float. As an in-water weight for a 20.00 g piece, 3.32 is 13.98 g. Jadeite at GIA’s 3.34 reads 14.01 g; nephrite at 2.95, 13.22 g; glass, aventurine and serpentine about 12.2 to 12.5 g.
- Where the line fails. The jadeite sheet’s density reaches down to 3.24 (13.83 g) and Hobbs reports albite-rich jadeite rock as low as 2.90 (13.10 g). Vesuvianite reads 13.98 to 14.17 g and grossular 14.44 g, both above the line. The line sorts; the refractometer identifies.
- The folk tests, scored. Touch catches glass and plastic only. A scratch shows only that a piece is too soft, and bowenite reaches 6. Backlighting can make a white piece with one green spot look all green (GIA). A UV lamp points to polymer or dye, not to fakes. No fetched source supports a lighter test.
- Treated jade is real jade. GIA’s buyer’s guide calls bleached, polymer-impregnated jadeite B jade and dyed material C jade. Fritsch and co-authors found infrared spectroscopy the only conclusive test for the polymer, so a home test cannot clear treatment. Dye is also covered on how to tell if a crystal is dyed.
| What it could be | Hardness (sheet) | Density (sheet) | 20.00 g piece in water | Against the 13.98 g line | Spot reading (Hobbs) | Folk test it passes |
|---|---|---|---|---|---|---|
| Jadeite | 6 to 7 | 3.24 to 3.43 | 13.83 to 14.17 g | Mostly above | 1.66 | All of them, by definition |
| Nephrite (actinolite; tremolite sheets) | 5 to 6 | 3.03 to 3.24; 2.99 to 3.03 | 13.31 to 13.83 g | Below | 1.61 to 1.62 | All of them, by definition |
| Vesuvianite (idocrase, “American jade”) | 6 to 7 | 3.32 to 3.43 | 13.98 to 14.17 g | At or above: the line fails | 1.71 | Heft, scratch, cold touch |
| Grossular (hydrogrossular, “Transvaal jade”) | 6.5 to 7 | 3.594 | 14.44 g | Above: the line fails | 1.72 | Heft, scratch, cold touch |
| prehnite (“Japanese jade”) | 6 to 6.5 | 2.80 to 2.95 | 12.86 to 13.22 g | Below, with nephrite | 1.63 | Scratch, cold touch |
| Serpentine: antigorite; lizardite | 2.5 to 3.5; 2.5 | 2.65; 2.55 | 12.45 g; 12.16 g | Below | 1.56 | Cold touch; bowenite, to 6 in Hobbs, also passes a scratch |
| Aventurine quartz (“Indian jade”) | 7 | 2.65 | 12.45 g | Below | 1.54, 1.55 | Scratch, cold touch |
| “Metajade” glass | 5.5 to 6 (Hobbs) | 2.65 (Hobbs) | 12.45 g | Below | 1.510 | Flashlight |
| Calcite, dyed (“Mexican jade”) | 3 | 2.7102 | 12.62 g | Below | Blink 0.172 | Cold touch |
| B jade: bleached, polymer-impregnated jadeite | As jadeite | As jadeite | As jadeite | Above | 1.66 | All home tests; infrared spectroscopy needed |
How to tell if jade is real: five steps, day one to laboratory
Start with a 10x lens and a scale reading to 0.01 g; finish at a gem laboratory if the piece matters. Day one needs only those, a thread, and a cup of water. A refractometer is step three, and a laboratory step five. Each step narrows the list; none of the first four can clear treatment.
- Look. Hobbs, “The Jade Enigma”, Gems & Gemology, Spring 1982 describes jadeite as granular, with a sugar-like granular fracture and often a dimpled polish, and nephrite as fibrous and greasy. Aventurine quartz glitters with fuchsite platelets; metajade glass shows a fern-like pattern and gas bubbles; dye collects in fractures.
- Weigh in water. Apply the 13.98 g line, below. Method: how to measure specific gravity at home.
- Refractometer spot reading. Hobbs gives jadeite about 1.66 and nephrite 1.61 to 1.62; most simulants read lower, and idocrase and grossular higher.
- UV lamp, as a pointer to treatment only; see the last section.
- Laboratory: infrared spectroscopy for polymer, Raman spectroscopy for omphacite, X-ray diffraction for mixtures, per GIA and Hobbs.
The finish state is one of five labels: jadeite jade; nephrite; not jade, simulant named; jade, treatment untested; or untested. The species numbers are on jadeite, and the other identification guides at the collecting guides.
Does the touch test, scratch test or flashlight test work?
Touch. Hobbs records the tradition of identifying jade by feel and concludes that the feel of jade is best left as a questionable means of detection. What touch can do: glass and plastic feel warm, crystalline materials cold, so every jade simulant other than glass and plastic should also feel cold at first. A cold stone is not thereby jade.
Scratch. Hobbs says hardness tests will determine that a gem material is too soft to be jadeite, will not identify it, and catch only a few simulants: serpentine, calcite and talc. Bowenite serpentine can reach 6, and aventurine quartz and grossular are as hard as jade or harder. A scratch also marks the piece; see how to test mineral hardness properly.
Flashlight. GIA writes that jadeite’s structure scatters light, and that, if properly cut, a white piece with a small green spot will make the gem appear completely green if lit from behind. A torch behind a stone shows translucency, which glass also has; it can exaggerate the colour of real jadeite. GIA’s laboratory also documented, in 2024, an omphacite jade carving backed with a 0.10 mm metallic film that gave it a see-through look.
Lighter, and water drops. No source fetched for this page, GIA’s or the International Gem Society’s, describes a flame or a water-drop test, so this page gives neither. The water test the sources support is the hydrostatic weighing below.
Is my jade real or glass? The 13.98 g line
The 13.98 g line: a 20.00 g piece that weighs more than 13.98 g in water is at or above specific gravity 3.32, consistent with jadeite; lighter, it is nephrite or most simulants. Hobbs used a 3.32 laboratory heavy liquid in which jadeite stays suspended or sinks slowly while nephrite and most simulants rise. Weighing in water applies the same threshold without the liquid: in-water weight is 20 − 20/3.32 = 13.98 g.
Worked. GIA’s jadeite at 3.34 reads 14.01 g, its nephrite at 2.95 reads 13.22 g. From the sheets: actinolite 13.40 to 13.83 g, tremolite 13.31 to 13.40 g, prehnite 12.86 to 13.22 g, quartz and antigorite 12.45 g, lizardite 12.16 g, calcite 12.62 g. Hobbs’s metajade glass at 2.65 also reads 12.45 g, the same weight as quartz on the live quartz page.
The documented failures. The jadeite sheet runs from 3.24 to 3.43, so low-density jadeite reads 13.83 g, under the line, and Hobbs reports albite-rich jadeite rock as low as 2.90. Above the line sit vesuvianite (3.32 to 3.43, 13.98 to 14.17 g) and grossular (3.594, 14.44 g); Hobbs separates them by refractive index. Hobbs adds that only prehnite could be confused with nephrite by specific gravity. General imitations are on how to tell if a crystal is fake.
Real jade, treated: A, B and C jade under the UV lamp
Treated jade is still jade. GIA’s buyer’s guide describes the Chinese classification: A jade, natural or polished with wax only; B jade, bleached with acid and impregnated with polymer resin; C jade, dyed. The guide also says jade can be dyed, bleached, heated, waxed and impregnated. B jade is jadeite, so it passes every test above.
The UV lamp is a pointer, not a test. In a Fall 2015 Gems & Gemology lab note, GIA’s Carlsbad laboratory reported a carved, polymer-impregnated jadeite in which long-wave UV produced strong green-yellow fluorescence from the dyed green areas but not from the naturally green area, and the colourless areas were inert. GIA wrote that strong fluorescence in jadeite often indicates polymer or dye, that polymer fluorescence is evenly distributed, and that testing only one portion might convince an observer that no dye had been applied.
What proves it. Fritsch and co-authors, Gems & Gemology, Fall 1992 found infrared spectroscopy the only method that conclusively showed polymer impregnation in all cases. Even that needs care: in GIA’s 2024 lab note, an infrared beam passed through a backing film’s glue gave a false positive for polymer. None of the jadeite, nephrite or serpentine sheets prints a luminescence line, by a ligature-aware search. This page gives no buying advice. Nothing on this site is offered for sale; the wanted list is the only commercial route.