Types of Fiber
A practical guide to fiber types and what mills do with them
Different fibers require different processing. The mill that does excellent work with Romney wool may not have the equipment for cashmere or alpaca. Knowing your fiber type helps you find the right mill and ask the right questions.
Sheep wool
The most commonly processed fiber. Sheep breeds produce wool ranging from ultra-fine (17 microns) to coarse carpet-grade (40+ microns). The breed determines what the fiber is good for and how it should be processed.
| Breed | Micron range | Character | Best for |
|---|---|---|---|
| Merino | 17 – 24 | Very fine, soft | Next-to-skin wear, baby items |
| Corriedale | 25 – 31 | Medium, versatile | All-purpose knitting, weaving, felting |
| Romney | 29 – 36 | Long staple, durable | Outerwear, rugs, bags |
| Shetland | 23 – 28 | Fine, heritage | Traditional knitting, lace |
| BFL (Bluefaced Leicester) | 24 – 28 | Lustrous, soft | Socks, shawls |
| Jacob | 27 – 35 | Natural colors, medium | Tweedy yarn, felting |
Most US fiber mills process sheep wool. If you raise a common breed, finding a mill is straightforward — use our directory to search by state.
Alpaca
Softer than most sheep wool, hypoallergenic, and available in over 20 natural colors. Two breeds:
- Huacaya — Fluffy, crimpy fiber similar in structure to sheep wool. Processes well on standard equipment with adjusted settings.
- Suri — Silky, lustrous fiber with no crimp. Produces drapey yarn with sheen. Requires more care during processing.
Alpaca lacks the elasticity of wool, so it is often blended with merino or other sheep wool for bounce and memory. Mills processing alpaca need different carder and spinner settings than those for sheep wool — confirm your mill has experience with alpaca before sending fiber.
Mohair
From Angora goats (not Angora rabbits — a common confusion). Mohair is lustrous, strong, and takes dye exceptionally well. Kid mohair (from young goats) is finer and softer than adult mohair. Often blended with wool for sheen and durability.
Cashmere
The fine undercoat of cashmere goats — one of the softest natural fibers at 15 to 19 microns. Each goat produces only 4 to 6 ounces of usable cashmere per year. Processing requires dehairing to separate the fine undercoat from the coarse guard hair. Not all mills have dehairing equipment — this is a specialty service.
Llama
Similar to alpaca but generally coarser. Llama is a double-coated animal, meaning the soft undercoat must be separated from the coarse guard hair (dehairing). The undercoat is warm and lightweight. Like alpaca, llama fiber lacks elasticity and benefits from blending with wool.
Angora
From Angora rabbits. Extremely soft and fluffy with a distinctive halo. Pure angora is slippery and difficult to spin on its own — it is usually blended with wool or silk for structure. Small quantities per animal (a few ounces per harvest) make it a luxury fiber.
Other specialty fibers
- Yak — Fine, warm undercoat similar to cashmere. Requires dehairing. Few US mills process yak.
- Bison — Extremely warm undercoat, shed naturally in spring. Requires dehairing. A niche fiber with limited mill options.
- Silk — Not an animal fiber in the same sense, but commonly blended with wool or alpaca for sheen and drape. Most mills that offer custom blending can add silk to your fiber.
What micron count means for processing
Micron count — the diameter of individual fiber strands — determines how a fiber feels and how it should be processed. Lower numbers mean finer, softer fiber:
- Under 20 microns: Very fine (merino, cashmere). Soft enough for next-to-skin wear. Requires careful processing to avoid felting.
- 20 – 30 microns: Medium (Corriedale, BFL, alpaca). Versatile. The sweet spot for most mill processing.
- Over 30 microns: Coarse (Romney, some longwools). Durable but not suitable for next-to-skin use. Good for outerwear, rugs, and bags.
Mills use micron count to set their equipment. If you know your fiber’s micron count (from a fiber test or breed average), share it with your mill.
Find a mill for your fiber
Use our directory to filter mills by fiber type. Not all mills process all fibers — especially specialty fibers like cashmere, yak, or bison that require dehairing equipment. Each listing shows which fiber types the mill accepts.
For definitions of processing terms used on this page, see our glossary.