The valuable jade. Denser and harder than nephrite, and the material behind imperial green.
Myanmar (jadeite), China, Canada, New Zealand, Guatemala (nephrite and jadeite)4 references
Jadeite is a sodium aluminium pyroxene, and essentially all the historically significant material comes from a small area of northern Myanmar. It is harder than nephrite at 6.5–7, denser at 3.30–3.38, and it takes a brighter, more vitreous polish. It also occurs in a wider colour range: white, lavender, orange, black and the intense translucent green called imperial that sets the ceiling on jade prices worldwide.
Two things drive value, and colour is only the second. The first is translucency — the trade calls it water — and fine jadeite has a glowing depth as though light is coming back out of the stone rather than off it. A vividly green but opaque piece is worth a small fraction of a slightly paler translucent one.
The third factor is treatment, and it dominates everything at the retail end. The Type A/B/C system exists because acid bleaching and polymer impregnation transform poor material into something that looks fine, and the change is invisible without instruments. Under a loupe, treated stone sometimes shows a faint network of etched channels where the acid attacked grain boundaries, and polymer can give a slightly resinous surface lustre — but the honest answer is that this needs a laboratory, and for jadeite of any value a certificate is standard practice rather than caution.
Type A (untreated) · Type B (bleached and impregnated) · Type C (dyed) · Lavender jadeite
Establish which of these you are holding before judging it. A genuine piece read against another reference's rules will look wrong when it is not.
These apply to this model and not to the rest of Jade. Work them alongside the maker's general checks, not instead of them.
Type A, B and C jadeite are visually similar and differ in value by an order of magnitude or more. Gemmological laboratories test this routinely using infrared spectroscopy. On a serious purchase the certificate is part of the transaction, not an optional extra, and a seller who resists one is telling you something.
Jadeite is the densest of the green stones in play. A measured specific gravity of 3.30–3.38 rules out nephrite, serpentine, quartzite and glass in one number.
Hold the piece against a light. Fine jadeite glows with depth — light appears to come back out of the stone. Opaque bright green is worth far less than slightly paler translucent material, and a buyer who prices on colour alone will overpay for the wrong thing.
Acid bleaching attacks grain boundaries and can leave a faint interconnected network of fine channels on the surface, sometimes with a slightly waxy or resinous lustre from the polymer that followed. It is suggestive rather than conclusive, and it points at Type B.
Vast range. Commercial Type A cabochons run tens to hundreds; fine imperial green jadeite reaches six and seven figures at auction.
An orientation for honest, unrestored condition — never an appraisal, and never a quotation.
Lovenhall StoneThe tests tell you what it is. The instrument reads a photograph and offers a name to start from — then hands you back to the tile and the coin, which are what settle it.