Buyer guide · Fineness
Cashmere Micron & Grade Chart
Cashmere fineness is the mean fiber diameter in microns (µm). Fiber may only be labeled cashmere in the US if it averages 19 µm or finer, and China's national standard sorts raw cashmere into four fineness types, from ultrafine (14.5 µm or finer) to coarse (up to 18.5 µm).
The legal definition of cashmere
Under the US Wool Products Labeling Act and the FTC rules, only fiber that meets the conditions below may be labeled cashmere. The Cashmere and Camel Hair Manufacturers Institute (CCMI) uses the same definition and refers to IWTO Test Method 8.
| Criterion | Limit |
|---|---|
| Fiber | Fine (dehaired) undercoat of the cashmere goat (Capra hircus laniger) |
| Mean fiber diameter | 19 µm or finer |
| Coefficient of variation of diameter | 24% or lower |
| Fibers coarser than 30 µm | 3% by weight or less |
China's fineness types (GB 18267-2013)
The Chinese national standard for cashmere counts fibers of 25 µm and finer as cashmere down and classifies raw cashmere by mean diameter. In the 2017 national inspection data published by China's market regulator, the average raw cashmere was 15.6 µm (Inner Mongolia: 15.7 µm).
| Type | Mean diameter | Share of raw cashmere inspected in 2017 |
|---|---|---|
| Ultrafine | 14.5 µm or finer | 1.89% |
| Extrafine | over 14.5 to 15.5 µm | 33.90% |
| Fine | over 15.5 to 16.0 µm | 46.21% |
| Coarse | over 16.0 to 18.5 µm | 18.00% |
For dehaired cashmere, the same standard writes the quality as a code: two letters (D for dehaired, plus W, G or B for white, gray or brown), five digits for mean diameter, mean length and guard-hair content, and six letters (A, B or C) for other characteristics. A white lot of 15.4 µm, 36 mm and 0.2% guard hair, for example, starts with DW54362. A replacement edition, GB 18267-2026, takes effect on May 1, 2027, so check which edition a test report cites.
| Dehaired cashmere characteristic | Class A | Class B |
|---|---|---|
| Coefficient of variation of diameter | ≤ 21% | ≤ 23% |
| Coefficient of variation of length | ≤ 50% | ≤ 54% |
| Foreign matter | ≤ 0.2% | ≤ 0.3% |
| Dark fibers (white cashmere only) | ≤ 15 per 5 g | ≤ 30 per 5 g |
| Mean bundle breaking tenacity | ≥ 3.5 cN/tex | ≥ 3.2 cN/tex |
Values beyond Class B are Class C. Short-fiber classes depend on mean length; see our fiber length guide.
Mongolian dehaired grades
Mongolia grades dehaired cashmere by mean diameter. The bands below are as reported in the 2024 value chain analysis of Mongolian cashmere carried out for the European Union (VCA4D).
| Grade | Mean diameter |
|---|---|
| Premium | 12.0–15.5 µm |
| MNF | 15.51–16.2 µm |
| I | 16.21–16.8 µm |
| II | 16.81–17.50 µm |
| III | 17.51–19.0 µm |
What "Grade A cashmere" means
Neither the US definition nor GB 18267 defines a fineness class called "Grade A". In GB 18267 the letters A, B and C rate other characteristics, such as diameter variation or short fiber. When a supplier quotes "Grade A", ask for the mean diameter, its coefficient of variation and the test method in writing.
How micron is measured
- Projection microscope (IWTO-8, GB/T 10685). The reference method in the CCMI definition, and the arbitration method in GB 18267.
- Laserscan (IWTO-12) and OFDA (IWTO-47, GB/T 21030). Faster instrument methods that also report the diameter distribution.
Methods do not always agree: in Interwoollabs round trials on wool tops finer than 26 µm, mean diameters measured by different IWTO methods differed by up to 0.3 µm. For a contract, name the method and the laboratory.
How to specify micron in an inquiry
- A target mean diameter and an acceptable range, for example 15.5 µm ± 0.3 µm.
- A maximum coefficient of variation of diameter, if your spinning needs it.
- Color, mean length and guard-hair limit, because they are priced together with micron.
- The test method and the lab you will use to check our trial lot.
Our typical dehaired lots are 14.3–15.8 µm, selected lot by lot. Send your target spec or ask for a trial lot.
Sources
- 15 U.S.C. § 68b(a)(6) — Wool Products Labeling Act, definition of cashmere
- 16 CFR § 300.19 — FTC rule on the terms “mohair” and “cashmere”
- CCMI — Definition of cashmere, fine and superfine wool
- GB 18267-2013 Cashmere (山羊绒), national standard of China — tables 2 and 6
- National standards platform — GB 18267-2026 replaces GB 18267-2013
- SAMR — 2017 national cashmere quality report (山羊绒质量情况通报)
- VCA4D (EU) — Cashmere value chain analysis in Mongolia, 2024
- AWTA — Comparison of diameter measurement technologies, Interwoollabs round trials
Ready to check this spec against a real lot?
Ask for a costing, a trial sample with test data, or an on-site inspection in China.