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When we talk about fleece we are always using words like density, crimp, sheen, handle, and fineness. I will try to explain some of these concepts. Density
Density is the concentration of fibers per unit of skin surface. The most accurate way to measure it is a microscopic counting of fibers in a determined area. This method has the clear advantage of counting the primary fibers (mostly medullated) as well as the secondary fibers that are the really fine ones that give the alpaca fiber its unique qualities. The disadvantage is that it is done with a skin biopsy and there are not many centers in the world that will do it or have the experience to do it. All breeders are used to checking the density by grabbing a handful of fiber on the animal if it is a suri, and or just pressing the huacaya fleece against the animal’s side to estimate the density. Because greater density is to our advantage when it comes to fiber production, it is a very desirable trait. 
Fineness
This is the fiber diameter. The finer it is, the softer it feels and the less guard hair is found. It is measured in microns and commonly ranges between 17 and 40 microns with more extremes possible over and under these values. It is measured in the histogram by laser scan technology, which is accurate, fast, inexpensive, and can measure large amounts of fiber. We are, by now, accustomed to using this technology and rely on it in making decisions about breeding, and the purchase of animals. Because the fiber is made of proteins, the nutrition and health of the animal has an important role in fiber diameter. For example, if a female does not nurse a cria, her nutrition goes to the fiber and the micron count can increase significantly. We have seen 4 points difference from one year to another and the only reason we could find was the relation to pregnancy and lactation. 
Sheen
This concept is better applied to the suri fiber, but is also of great importance in huacaya fiber. It is the light reflection off the surface of the fiber. The smoother the fiber, the better it reflects light, thus increasing the sheen. Because the free border of the suri fiber scales is finer and is less protruding, it gives better reflection of light compared to huacayas. With the breeding for fine fiber and for brilliance in the huacayas, we are also seeing a great deal of sheen in their fleeces too. See the picture of one of our huacaya alpaca’s fiber. Handle
It is a very subjective quality. Peruvian breeders consider this the most important attribute of the alpaca fiber. Note that Peru still owns 80 % of the alpaca population in the world and produces most of the fiber in the world market. In that country, there are women who for generations have dedicated their lives to touching and sorting fiber by the so-called handle. It is a subjective measure of fineness, softness and uniformity in the fiber. The best fiber just feels good to the touch. Uniformity
This is measured by the standard deviation and coefficient of variation in the histogram. The standard deviation (SD) is a statistical term that indicates the degree of variation from the average diameter measured in a fiber sample. The coefficient of variation (CV) indicates the SD as a percentage or average. It is calculated by dividing the SD by the mean diameter and then multiplying by 100. So the lower the Standard Deviation and the Coefficient of Variation, the more uniform the fleece is, because most of the fibers have a diameter close or similar to the mean diameter measured. The higher the CV the more diverse is the fiber diameter in the sample and the wider the curve will be in the histogram. 
Crimp
This is the sweetheart word of the alpaca breeders’ community. We call the waviness of the huacaya fiber “crimp”. The waves are organized and appear like ridges in a lock of fiber. We tend to call the individual waviness of a fiber “crinkle”. The waviness of the crinkle can be measured in the fiber curvature, a term that I am not used to utilizing, since I am more used to appreciating the crimp by naked eye. As we commented in the fiber structure, crimp may indicate fineness of the fiber. Bundling
It refers to the clumping together of fibers in large groups; they look like fingers when the fiber is parted. This is a fiber characteristic well sought after by the alpaca breeders community. 
How we assess our production
The parameters that we all use to assess the yearly fiber production on our farms include the histogram of fiber thickness and the fleece weight at the time of shearing. Sometimes the staple length is also registered. These controls allow us to check our herd health, nutrition and no less important, to asses the genetic value of our animals and make the necessary corrections. Each alpaca produces at least three different quality fibers in its fleece. The best (finest, softest, shiniest and quickest growing after shearing) is found up on the trunk of the body, between the shoulders and the rump, with shorter, though, fine fibers on the neck, and coarser fibers in the apron, belly and chest. Therefore, we separate the fiber collected at the time of shearing into blanket, neck and legs. Sometimes we feel tempted to use the neck fiber along with the blanket since it is so soft in some animals, but being shorter, it may produce the pilling phenomenon in a garment after a short time of use. All the fiber has some use and even the thickest one can be used in rough materials like carpets or upholstery. The next class up can be used in accessories like hats, socks and mittens, and the best fiber is used in garments to be worn close to the skin. The international fiber market has its own classification of fiber for different purposes as requested by the mills. The reference books consulted about technical issues for this limited article are: - Alpacas-Synthesis of a Miracle, by Michael Safley.
- The Alpaca Book. Management, Medicine, Biology, and Fiber. By Authors; Eric Hoffman and Murray E. Fowler, DVM (1995 edition)
- Animal Breeding and Production of American Camelids by Professor Rigoberto Calle Escobar, DVM (1984 edition)
Pictures from Andes Alpaca Farm huacaya alpacas.
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