Every year two billion kilograms of wool are produced worldwide. The most prized variety comes from the fleece of merino sheep that are shorn once a year and their fleeces have fine and very curly fibers, used exclusively for clothing.
The most prestigious wool is called superfine, amounting to a mere 15% of annual production, which comes with an average fineness of less than 19.5 micron (thousandths of a millimeter). Every year, Lanificio Ermenegildo Zegna selects and buys the best batches of wool in auctions in Australia.
There are around 20 parameters for classifying wools. The key parameters are fineness, length, cleanness, strength, limited percentage of short fibers, uniformity of length and fineness, color, absence of impurity, style.
Only one of these is objectively measurable and thus indisputable:
Fineness means the average diameter of the fiber.
The standard unit of measurement is the micron (µ), which is one thousandth of a millimeter.