Polymer-and-Dye — The Type B+C Treatment for Jadeite
Polymer-and-Dye — The Type B+C Treatment for Jadeite
A combined enhancement that bleaches, impregnates, and dyes — significant, disclosed, and durability-impaired
Polymer-and-dye is the combined treatment most commonly applied to jadeite, in which the stone is first bleached and impregnated with a polymer resin to improve transparency and structural integrity, then dyed to enhance or alter colour. Laboratories designate the result Type B+C jadeite, distinguishing it from untreated Type A, polymer-impregnated-only Type B, and dyed-only Type C. The combined treatment is one of the most significant enhancements applied to a major commercial gem species and is required to be disclosed at every level of the trade.
Process
The starting material is typically lower-grade jadeite that has been judged commercially unsalable in its natural state, with insufficient colour, opaque or whitish ground, and visible iron staining or other surface discolouration. The first stage of treatment is acid bleaching: the stone is immersed in a strong acid that dissolves iron oxides and other staining materials, leaching them from the porous polycrystalline structure and leaving a clean but now structurally weakened material. The second stage is polymer impregnation, in which the bleached stone is placed under vacuum and pressure with a thermosetting resin that infiltrates the pore network and stabilises the structure. The third stage is dyeing, in which a coloured dye — typically green to imitate fine imperial jadeite, but also lavender, orange, or other colours — is introduced either as a separate step or in combination with the polymer.
The result is a material that visually approximates higher-quality untreated jadeite but is structurally and chemically different from it. Polymer-and-dye jadeite is less durable than Type A material, susceptible to colour fading and polymer yellowing over time, and vulnerable to deterioration under heat, ultrasonic cleaning, and exposure to organic solvents.
Detection
Gemmological laboratories detect polymer-and-dye treatment through a combination of methods. Infrared spectroscopy reveals absorption features characteristic of organic resins, particularly in the C-H stretching region around 3000 cm-1. Microscopic examination shows characteristic features including dye concentration in fissures and grain boundaries, blue or green fluorescence under long-wave ultraviolet light from selected polymer types, and a network of absorption-band patterns visible in the dyed colour zones. Spectroscopy in the visible range can distinguish dye colours from natural chromium- or iron-induced colour in jadeite.
Laboratory testing is the standard method of confirming Type A status for fine jadeite, and reputable dealers in the upper end of the jadeite trade routinely commission laboratory reports on stones above commercial thresholds.
Disclosure
Polymer-and-dye treatment must be disclosed at point of sale. The Asian fine-jewellery trade, where jadeite is most actively traded, has well-developed conventions for disclosure: laboratory reports specify the treatment status as Type A, Type B, Type C, or Type B+C, and these designations are commonly stamped or noted on certificates accompanying the stone. Western jewellers selling jadeite are obligated by major industry codes — including those of the Jewelers of America and the AGTA — to disclose treatment status as a routine part of the sale.
Durability and care
Polymer-and-dye jadeite is notably less durable than Type A material. The polymer can yellow over time, particularly with ultraviolet exposure; the dye can fade or shift in colour, particularly in lavender and intense green hues; and the underlying acid-bleached structure is more friable than untreated jadeite. The material should be cleaned only by gentle wiping with a soft cloth, kept away from heat sources, and avoided from ultrasonic and steam cleaning. With proper care, the apparent quality may be retained for years; without it, deterioration can be visible within months.
In the trade
Polymer-and-dye jadeite occupies a substantial commercial position in the lower and mid-range jadeite market, where the price gap between untreated material of fine quality and treated material approximating that quality is large. Customers should expect significant disclosure and price discounts relative to Type A material. The treatment is not deceptive when disclosed; it becomes deceptive when sold as untreated, and consumer protection in this category depends entirely on accurate disclosure at every step of the supply chain.