A suspiciously cheap consignment of "pure muga"
A weaver-owned cooperative in Kamrup buys muga yarn for its mekhela chador line. A trader offers 8 kg of yarn described as "pure muga, machine-reeled" at ₹4,300/kg, against the ₹6,200/kg the cooperative normally pays a local rearer. The yarn is a uniform deep gold over the whole hank, very glossy, and slightly stiffer than the yarn the members are used to. Payment is demanded in cash, and the trader will not name the reeling unit or give a bill. The loom supervisor has one afternoon and a small sample to decide. The season's biggest order depends on the yarn. Separately, members have asked whether they could simply switch to eri silk, which is cheaper and easier to dye, and market the product on an "ahimsa silk" claim.
1. Which tests can the supervisor run on the sample, and what does each test actually prove - or fail to prove?
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Burn test. A fibre snippet burns like a protein: it shrivels, smells of burnt feather, self-extinguishes, and leaves a crushable black bead. This separates silk from cotton (paper smell, soft grey ash) or polyester (melts, hard bead). It does not distinguish muga from mulberry silk, because both are protein. Anyone using the burn test to "prove" muga is making an unsupported claim.
Wet rub / soap test. Rub a hank in warm soap solution against white cloth. A dyed yarn bleeds colour; the natural gold of muga lies in the fibre and does not bleed as a surface dye. Strong bleeding is a red flag for dyed mulberry.
Microscopy. Mulberry silk shows a triangular cross-section; muga and other wild silks are flatter, ribbon-like and striated.
Chemical behaviour. Mulberry silk is degraded more readily by chlorine bleach and alkali than wild silks such as muga; a controlled bleach spot test can support, not replace, microscopy.
Commercial check. Yarn at 30% below the local rate, with no bill and no named reeling unit, is itself evidence.
2. What should the cooperative do about this consignment, and what sourcing rules should follow?
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Immediate decision: do not pay cash and do not put the yarn into a muga-labelled product on the strength of the trader's word. A 30% discount is not a bargain if the yarn is dyed mulberry: mislabelling a muga mekhela chador destroys buyer trust and undermines the GI protection that gives muga its price premium.
Practical route:
- Buy 100–200 g only, with a written declaration of species and origin signed by the trader.
- Send it for a laboratory fibre test (microscopy plus solubility); keep the report with the lot number.
- Meanwhile run the soap-rub test in-house. If colour bleeds, reject outright.
- If the test passes, buy one beam's worth, not 8 kg, and verify performance on the loom before committing.
Standing rules: purchase only against invoice and lot number; record rearer/reeler name, weight and date in a register; pay by bank transfer; retain a sample from every lot; buy directly from rearers where possible; and print the lot reference on the product tag so any claim can be traced.
3. A member proposes switching the mekhela chador line to eri silk and marketing it as ahimsa silk. Evaluate this.
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Technically and commercially, eri is not a substitute for muga in the same product. Eri (Samia ricini) is a white, soft, bulky spun silk from open cocoons; it has lower tenacity and higher elongation than muga, dyes easily, and gives a warm, softly draping cloth. Muga (Antheraea assamensis) is a golden, stiff-lustred, strong reeled wild silk. A mekhela chador made in eri would look, drape and wear differently and cannot carry the muga price.
The ahimsa claim is legitimate for eri - the cocoons are harvested after the moth emerges, so no insect is stifled. It is not a legitimate claim for muga, where cocoons are stifled.
Recommendation: keep the muga line and its price, and develop eri as a separate, honestly labelled line (eri chador, stoles, shawls) aimed at a different buyer. Never dye eri gold and label it muga - that is mislabelling and risks action under consumer and GI rules. Cost the eri line separately, because its lower yarn price is offset by higher bulk and lower strength.