Sea silk is an extremely fine, rare, and valuable fabric that is made from the long silky filaments or byssus secreted by a gland in the foot of pen shells (particularly Pinna nobilis). The byssus is used by the clam to attach itself to the sea bed.
Sea silk was produced in the Mediterranean region from the large marine bivalve mollusc Pinna nobilis until early in the 20th century. The shell, which is sometimes almost a metre long, adheres itself to rocks with a tuft of very strong thin fibres, pointed end down, in the intertidal zone. These byssus or filaments (which can be up to 6 cm long) are spun and, when treated with lemon juice, turn a golden colour, which never fades.
The cloth produced from these filaments can be woven even finer than silk, and is extremely light and warm; however, it attracts clothes moths, the larvae of which will eat it. It was said that a pair of women's gloves could fit into half a walnut shell and a pair of stockings in a snuffbox. The mollusc is also sought for its flesh and occasionally has pearls of fair quality.
The Greek text of the (196 BCE) Rosetta Stone records that Ptolemy V reduced taxes on priests, including one paid in byssus cloth, usually translated as "fine linen cloth". In Ancient Egyptian burial customs, byssus cloth (actually linen) was used to wrap mummies.
Nor was it enough to comb and to sow the materials for a tunic. It was necessary also to fish for one's dress; for fleeces are obtained from the sea where shells of extraordinary size are furnished with tufts of mossy hair.
Roman Empire 
The Byzantine historian Procopius's (ca. 550 CE) Persian War, "stated that the five hereditary satraps (governors) of Armenia who received their insignia from the Roman Emperor were given chlamys (or cloaks) made from lana pinna. Apparently only the ruling classes were allowed to wear these chlamys."
At a certain period of the year an animal is seen running out of the sea and rubbing itself against certain stones of the littoral, whereupon it deposes a kind of wool of silken hue and golden colour. This wool is very rare and highly esteemed, and nothing of it is allowed to waste.
The (3rd century CE) Weilüe "Brief Account of the Wei", which was an unofficial history of the Cao Wei empire (220-265 CE), records haixi 海西 "West of the Sea" cloth made from shuiyang 水羊 "water sheep".
They have fine brocaded cloth that is said to be made from the down of 'water-sheep'. It is called Haixi ('Egyptian') cloth. This country produces the six domestic animals [traditionally: horses, cattle, sheep, chickens, dogs and pigs], which are all said to come from the water. It is said that they not only use sheep's wool, but also bark from trees, or the silk from wild silkworms, to make brocade, mats, pile rugs, woven cloth and curtains, all of them of good quality, and with brighter colours than those made in the countries of Haidong (“East of the Sea”).
The (ca. 5th century CE) Hou Hanshu "Book of the Eastern Han" expresses doubt about "water sheep" in the "Products of Daqin (the Roman Empire)" section. "They also have a fine cloth which some people say is made from the down of 'water sheep,' but which is made, in fact, from the cocoons of wild silkworms". The historian Fan Ye (398-445 CE), author of the Hou Hanshu, notes this section's information comes from the report that General Ban Yong 班勇 (son of General Ban Chao 班超, 32-102 CE) presented to the Emperor in 125. Both Bans administered the Western Regions on the Silk Road.
The (945 CE) Tang shu "Book of Tang" mentioned Haixi cloth from Folin 佛菻 "Syria", which Emil Bretschneider first identified as sea silk from Greece. "There is also a stuff woven from the hair of sea-sheep, and called hai si pu (stuff from the western sea)". He notes, "This is, perhaps, the Byssus, a clothstuff woven up to the present time by the Mediterranean coast, especially in Southern Italy, from the thread-like excrescences of several sea-shells, (especially Pinna squamosa)."
In the midst of the South Sea are the houses of the kău people who dwell in the water like fish, but have not given up weaving at the loom. Their eyes have the power to weep, but what they bring forth is pearls.
This aquatic type of raw silk was called jiaoxiao 蛟綃 "mermaid silk" or jiaonujuan 蛟女絹" mermaid women's silk".
Unfortunately, in recent years, Pinna nobilis has become threatened with extinction, partly due to overfishing, the decline in seagrass fields, and pollution. As it has declined so dramatically, the once small but vibrant sea silk industry has almost disappeared, and the art is now preserved only by a few women on the island of Sant'Antioco near Sardinia.
- Webster's Third New International Dictionary (Unabridged) 1976. G. & C. Merriam Co., p. 307.
- Oxford English Dictionary (1971), under Byssus.
- Translation of the Greek section of the Rosetta Stone.
- Book I, Alciphron, Literally and Completely Translated
- Tr. Laufer 1915:109.
- Verrill, A. Hyatt (1950), Shell Collector’s Handbook, New York: Putnam, p. 77
- McKinley, Daniel (1999), “Pinna And Her Silken Beard: A Foray Into Historical Misappropriations,” Ars Textrina 29, pp. 9-29
- Maeder 2002, p. 10.
- Turner and Rosewater 1958, p. 294.
- Tr. Laufer 1915:111.
- In Modern Standard Chinese usage, Haixi denotes "western; foreign" names such as Haixi Jurchens and Haixi Mongol and Tibetan Autonomous Prefecture.
- Tr. Hill 2004
- Tr. Hill 2003.
- Tr. Bretschneider 1871, p. 24
- Tr. Schafer 1967:220-1.
- Maeder, Hänggi, and Wunderlin 2004, pp. 68-71.
- OED2, under Sea, n. 23 (d).
- Bretschneider, Emil. 1871. On the Knowledge Possessed by the Ancient Chinese of the Arabs and Arabian Colonies and Other Western Countries. Trubner.
- Hill, John E. (2009) Through the Jade Gate to Rome: A Study of the Silk Routes during the Later Han Dynasty, 1st to 2nd Centuries CE. John E. Hill. BookSurge, Charleston, South Carolina. ISBN 978-1-4392-2134-1. See Section 12 plus "Appendix B - Sea Silk".
- Hill, John E. 2004. The Peoples of the West. A draft annotated translation of the 3rd century Weilüe – see Section 12 of the text and Appendix D.
- Laufer, Berthold. 1915. "The Story of the Pinna and the Syrian Lamb", The Journal of American Folk-lore 28.108:103-128.
- McKinley, Daniel L. 1988. "Pinna and Her Silken Beard: A Foray Into Historical Misappropriations". Ars Textrina: A Journal of Textiles and Costumes, Vol. Twenty-nine, June, 1998, Winnipeg, Canada, pp. 9–223.
- Maeder, Felicitas 2002. "The project Sea-silk – Rediscovering an Ancient Textile Material." Archaeological Textiles Newsletter, Number 35, Autumn 2002, pp. 8–11.
- Maeder, Felicitas, Hänggi, Ambros and Wunderlin, Dominik, Eds. 2004. Bisso marino : Fili d’oro dal fondo del mare – Muschelseide : Goldene Fäden vom Meeresgrund. Naturhistoriches Museum and Museum der Kulturen, Basel, Switzerland. (In Italian and German).
- Schafer, Edward H. 1967. The Vermillion Bird: T'ang Images of the South. University of California Press.
- Turner, Ruth D. and Rosewater, Joseph 1958. "The Family Pinnidae in the Western Atlantic" Johnsonia, Vol. 3 No. 38, June 28, 1958, pp. 285–326.
- Byssus threads from mussel, Virtue School Project
- Byssus, Aquatext
- History of Sea Byssus cloth, Designboom
- How to Spin a Byssus Thread, Designboom
|Look up byssus in Wiktionary, the free dictionary.|
- Sticky When Wet, Science News
- Wet Wonder Glue[dead link], Waite Research Lab
- The PROJECT SEA-SILK (Bisso marino), Natural History Museum of Basel