Bissye — Sea Silk and Byssus Fibre | bissye.com
Byssus measures 10 to 50 microns, silk 11 to 15, merino wool 18 to 25 and mohair 20 to 40 — and the beard that supplies it reaches 20 centimetres.
Byssus fibres are 10 to 50 microns in diameter. Silk runs 11 to 15 microns, merino wool 18 to 25 and mohair 20 to 40, so byssus holds both the finest lower bound and the coarsest upper bound of the four.
The range is what distinguishes the fibre. A strand at the 10 micron end sits below silk's lower limit of 11; a strand at 50 microns sits above mohair's upper limit of 40. Sorting the beard is therefore part of preparing the fibre for spinning.
Length is a separate measure from diameter. The beards of Pinna nobilis can reach 20 centimetres, which is the stock from which the fibre is drawn — a beard dimension, not a thread thickness.
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Against wool and mohair the comparison favours byssus on the fine end: merino starts at 18 microns and mohair at 20, both well above byssus's 10 micron floor.
Silk is the closest comparator at 11 to 15 microns, but its range is narrow. Byssus at 10 to 50 microns covers five times that span, which is why cloth from the fibre varies in hand.
The figures above are the comparison set used throughout this entry: 10–50, 11–15, 18–25 and 20–40 microns, plus the 20 centimetre beard length.
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