Two readings decide most "jadeite" claims: a refractometer spot reading near 1.66 and a hydrostatic specific gravity near 3.34. We ran both on five retail bangles — and found that passing them still leaves the treatment claim wide open.
Editor score 4.0 / 5
In fourteen years of ordering jade at retail, the claim we test most often is the shortest one: "jadeite." Two numbers answer it in about twenty minutes — a refractive index spot reading and a hydrostatic specific gravity — and a third check, ten minutes at the loupe, tells you which of two different things the listing actually promised.
What most buyers miss is that "jadeite" and "Type A" are separate claims. The first is a mineral species. The second is a treatment status. Our logs for the past year include bangles that passed the species test at 1.66 and 3.33 and still failed the listing, because the surface had been acid-etched and refilled.
The two readings that settle the word "jadeite"
Jadeite and nephrite are both genuine jade, and neither is a fake. They are simply not interchangeable in price, and the instruments separate them with less ambiguity than any other pair in coloured stones.
| Property | Jadeite | Nephrite |
|---|---|---|
| Refractive index (spot) | 1.66 (range 1.666–1.680, ±0.008) | 1.61 (range 1.606–1.632) |
| Specific gravity | 3.34 (+0.06, −0.09) | 2.95 (practical tolerance 2.90–3.05) |
| Mohs hardness | 6.5–7.0 | 6.0–6.5 |
| Texture at 10x | Granular, sugary, interlocking pyroxene grains | Felted, fibrous, waxy, fibres run one direction |
| Loupe separator | Crystal faces catch the fibre-optic light on unpolished backs and inner rims | No crystal faces; a smooth, matted surface |
The roughly 0.4 gap in specific gravity is the single cleanest separator in the trade. A bangle that reads 3.33 is not nephrite. A bangle that reads 2.94 is not jadeite, no matter what the listing says.
What five recent orders actually measured
Representative bangles bought at retail between 2023 and 2025, all sold under a jade or jadeite heading. Spot index is the refractometer reading taken on the flat of the inner rim; specific gravity is by hydrostatic weighing on the unset bangle.
| Listing claim | Spot RI | SG | 10x / 30x loupe | What it is |
|---|---|---|---|---|
| "Natural jadeite jade, Grade A," 56 mm inner diameter, 9 mm wall | 1.66 (two readings, 1.654 and 1.667) | 3.33 | Granular interlocking texture, sugary grain boundaries visible on the unpolished inner rim, 437 nm line in the hand spectroscope | Jadeite. Claim holds. |
| "Jadeite bangle, deep green, icy" | 1.56 | 2.61 | Felted fibrous structure, waxy polish, no granular faces | Bowenite (serpentine). Fails on the first reading. |
| "Type A jadeite, certificated" | 1.66 across five spots | 3.34 | Acid-etch pits, cobweb surface fractures, resin sheen in the pits, strong reaction under long-wave UV | Jadeite, yes — but bleached and impregnated. The "Type A" claim fails. |
| "Natural jade" (no mineral named) | 1.61 | 2.94 | Felted fibres, greasy lustre, soft-looking polish | Nephrite. Genuine jade, but not jadeite. |
| "Jadeite" | 1.72 | 3.31 | Massive and even, no sugary grain, greasy rather than vitreous polish | Californite (massive idocrase). Density sits right inside the jadeite band. |
On scoring day we rechecked asking prices at three retailers. The bangle that turned out to be bleached and impregnated was listed within 8 percent of a documented Type A piece of similar size and colour.
Where specific gravity alone will fool you
That last row is the reason we never stop at the scale. Californite holds a specific gravity of roughly 3.30, which is squarely inside the jadeite range, and grossular garnet sits at 3.48 — high enough to look like a heavy jadeite bangle to a buyer using density as the only screen. At the other end, quartz and chalcedony read near 2.60, glass lower still, and smithsonite reads 4.35 with a vague shadow edge near 1.62.
Specific gravity narrows the field. The refractive index names the stone. Californite is only caught because it reads 1.72 against jadeite's 1.66, and saussurite — which overlaps jadeite's density at 2.90–3.10 — often will not give a stable reading at all, because different grains in the same stone read differently. When a refractometer reading wanders between spots, treat that as a result in itself.
The loupe work the numbers cannot replace
At 10x, jadeite is a granular aggregate. Turn the bangle to the unpolished inner rim and you should find faceted crystal surfaces catching the fibre-optic light in a mosaic. Nephrite shows no such faces; its fibres are felted and directional, and the polish looks waxy rather than glassy. That single observation separates the two jades faster than any calculation, and it holds up on a 56 mm bangle with a thick wall where the refractometer only has one or two usable flat spots.
At 30x, we are hunting treatment, not species. Acid etching leaves fine pits and cobweb fractures at the surface. Dye collects along grain boundaries and inside cracks, so colour that looks evenly spread on a screen looks strung along fractures under a fibre-optic light. A flat, unvarying green with no depth at 30x is a warning; natural jadeite almost always shows internal variation when lit from the side.
Bench log, arriving order: spot RI 1.66 on five spots; SG 3.34; long-wave UV strong — species confirmed as jadeite, treatment status unresolved. Sent for infrared analysis.
Why "jadeite" and "Type A" are different promises
Row three of our table is the case that costs buyers the most money. Bleached, polymer-impregnated jadeite — "B jade" in the trade — is still jadeite. Its refractive index reads 1.65 or 1.66. Its specific gravity stays near 3.34 unless the impregnation is heavy, because polymers themselves sit below 2.5 on the density scale and only drag the total down when there is a lot of them. The 1992 Gems & Gemology study that first mapped this treatment found infrared spectroscopy to be the only test that conclusively detected polymer in every case; ordinary gemmological testing passed the material.
Two practical consequences follow. First, wax impregnation also counts as B jade — sellers who describe B jade as "resin-impregnated only" are using a technicality, and a heavily waxed bangle will often glow strongly under long-wave UV. Second, US law is on the buyer's side here: the Federal Trade Commission's Jewelry Guides require disclosure of treatments that significantly affect value or are not permanent, and bleached, impregnated jadeite falls into both categories.
What to ask before you pay
- Ask which mineral is claimed: jadeite or nephrite. A listing that only says "jade" is usually nephrite, and at a nephrite price that is fine — at a jadeite price it is not.
- Ask for the refractive index and specific gravity readings, not just the words "Type A." Readings without the range and the spot method are not a result.
- Prefer bangles over rings for verification. A bangle is unset, so the full hydrostatic calculation is clean; closed-backed rings and pendants add metal weight and block the refractometer.
- Check the report number with the issuing laboratory, and check that the report describes the piece you received, not a similar one.
The short version: two numbers will tell you whether the word "jadeite" is honest. They will not tell you whether the stone has been through an acid bath. Budget for both questions before you commit, and if a listing offering Type A jadeite undercuts comparable pieces by anything like a factor of ten, assume the answer to the second question is already written.