C-jade is the trade designation for jadeite that has been artificially coloured by the introduction of dye, most commonly to simulate the prized imperial green or lavender hues of natural-colour jadeite. The treatment almost invariably accompanies the acid-bleaching and polymer-impregnation process that defines B-jade, making the full designation B+C jade the more accurate description of most dyed commercial material. C-jade occupies the lowest tier of the jadeite quality hierarchy: it is significantly less valuable than either untreated jadeite (A-jade) or polymer-impregnated-only material, and its disclosure is mandatory under the trade standards of major gemmological bodies and international consumer-protection legislation in the principal markets of Hong Kong, mainland China, and Taiwan.

The Treatment Process

The production of C-jade follows a sequence that begins with the selection of low-quality jadeite rough or finished blanks carrying undesirable brown, grey, or mottled tones caused by iron-oxide staining or natural weathering. These pieces are first subjected to acid bleaching — typically using hydrochloric or oxalic acid — which dissolves the offending iron compounds and opens the interlocking grain boundaries of the jadeite's interlocking pyroxene crystals. This bleaching stage is identical to the first step in producing B-jade; the structural damage it inflicts on the stone's natural matrix is an unavoidable consequence.

Once bleached and rinsed, the porous, weakened material is immersed in a dye bath. Organic dyes — including chromium-based greens and synthetic violet or lavender colorants — are drawn into the opened grain boundaries under vacuum or pressure impregnation. The stone is then stabilised with an epoxy or polymer resin, which fills the structural voids created by bleaching, restores surface polish, and locks the dye in place. The polymer impregnation step is functionally identical to that used in B-jade production; the addition of dye is the defining characteristic that elevates the treatment to C-jade status.

The resulting material can, to the untrained eye, present a convincing simulation of fine green or lavender jadeite. Surface lustre is restored by the polymer coating, and the dye can be distributed with sufficient uniformity to mimic the even colour saturation of high-quality natural material. However, the treatment is inherently unstable: organic dyes are susceptible to photodegradation under prolonged ultraviolet or visible-light exposure, and the polymer matrix can be degraded by heat, harsh cleaning agents, and prolonged contact with perfumes or cosmetics. Colour fading over years of wear is a well-documented outcome.

Gemmological Detection

Experienced gemmologists and accredited laboratories can identify C-jade through a combination of techniques, none of which requires destructive testing.

• Spectroscopy: The Chelsea colour filter is a useful preliminary tool; many green dyes used in C-jade transmit red under the filter, whereas natural chromium-coloured imperial green jadeite also appears red — making the filter necessary but not sufficient on its own. Definitive identification relies on ultraviolet-visible (UV-Vis) spectroscopy. Natural chromium-green jadeite displays a characteristic absorption doublet at approximately 630–660 nm and a broad band in the blue region. Dyed green C-jade typically shows broad, diffuse absorption bands inconsistent with chromium, often centred around 630–670 nm but lacking the sharp doublet structure. Lavender dyes produce similarly anomalous spectra.
• Infrared spectroscopy (FTIR): Fourier-transform infrared spectroscopy detects the polymer resin component with high reliability, revealing absorption bands associated with epoxy compounds that are absent in untreated jadeite. FTIR is the standard confirmatory test for both B-jade and B+C jade at major gemmological laboratories.
• Magnification: Under fibre-optic illumination and magnification, the dye in C-jade frequently concentrates along grain boundaries and fractures, producing a network of colour-enriched lines — sometimes described as a "spiderweb" or "mossy" distribution — that differs markedly from the even, structurally integrated colour of natural jadeite. The surface may also show a waxy or resinous lustre inconsistent with the vitreous polish of untreated material.
• Ultraviolet fluorescence: The polymer resin in B+C jade commonly fluoresces a chalky blue-white or greenish-white under long-wave ultraviolet light, a response absent in most untreated jadeite. This is a useful screening indicator, though not all resins fluoresce identically.

Major gemmological laboratories — including the Gemmological Institute of America (GIA), the Hong Kong Jade and Stone Laboratory, and Lotus Gemology — routinely issue reports distinguishing A-jade, B-jade, and B+C (C-jade) material. Laboratory certification is considered essential for any jadeite transaction of commercial significance.

Market Context and Valuation

The commercial production of C-jade is concentrated in processing centres in Guangdong province, China, particularly in the city of Guangzhou and the town of Sihui, which together form the world's largest jadeite-cutting and treatment industry. Raw material originates almost entirely from Myanmar (Burma), the sole significant source of gem-quality jadeite. Lower-grade Burmese jadeite that would otherwise be unmarketable in its natural state is transformed by the B+C treatment process into material that can be sold at accessible price points in consumer markets across East and Southeast Asia.

The value differential between C-jade and equivalent-appearing natural jadeite is extreme. A cabochon of fine imperial-green A-jade may command tens of thousands to hundreds of thousands of US dollars per piece at auction; an outwardly similar C-jade piece of the same dimensions carries a value measured in tens to low hundreds of dollars at most. This disparity creates powerful economic incentives for misrepresentation, and undisclosed C-jade has been a persistent problem in retail markets, particularly in tourist-oriented jade markets in Hong Kong, Bangkok, and Yunnan province.

Hong Kong's Consumer Council and the Hong Kong Jade and Stone Laboratory have documented repeated instances of undisclosed treated jadeite being sold as natural material, and the Hong Kong Trade Descriptions Ordinance explicitly requires disclosure of treatments that materially affect value. In mainland China, the national standard GB/T 16553 governing the nomenclature of jewellery and gemstones requires that treated jadeite be labelled accordingly. Despite these regulatory frameworks, enforcement at the retail level remains inconsistent.

Durability and Care

The practical durability of C-jade is considerably inferior to that of untreated jadeite. Natural A-jade is renowned for its toughness — a consequence of its tightly interlocking crystalline microstructure — and its resistance to everyday wear. The acid-bleaching stage of C-jade production disrupts this microstructure, weakening the material and making it more susceptible to chipping and cracking under impact. The polymer filler compensates partially but does not restore the original mechanical integrity.

Colour stability is the more immediate concern for the owner of C-jade. Organic dyes are inherently fugitive under ultraviolet radiation; prolonged display in sunlit windows or under UV-rich lighting will cause progressive fading. Immersion in ultrasonic cleaning baths, exposure to steam cleaners, or contact with acetone-based solvents can dissolve or dislodge the polymer matrix, causing catastrophic colour loss. Owners of C-jade — whether knowingly or unknowingly acquired — should clean pieces only with a soft, damp cloth and avoid all chemical contact.

Disclosure and Ethical Considerations

The sale of C-jade without disclosure constitutes misrepresentation under the trade standards of every major gemmological body, including the GIA, the International Coloured Gemstone Association (ICA), and the American Gem Trade Association (AGTA). The AGTA Code of Ethics explicitly requires disclosure of all treatments that affect value or durability. For jadeite specifically, the GIA's grading reports and the reports of specialist jade laboratories provide the most reliable independent confirmation of treatment status.

Buyers purchasing jadeite at any price point above the purely decorative should insist on a current laboratory report from a recognised institution. The absence of such documentation, particularly when accompanied by pricing that appears anomalously low for the colour and apparent quality presented, should be treated as a significant caution.

Further Reading

• GIA Gems & Gemology — Jadeite Jade Treatments
• Lotus Gemology — Jadeite Treatments
• GIA Gem Encyclopedia — Jade