What Is Silk? History, Types and Production

Silk is a natural protein fibre, spun as a continuous filament by a silkworm to build its cocoon. That single fact explains almost everything else about it: the strength, the way it catches light, and why it costs more than a fabric woven from a shorter, chopped fibre like cotton or wool.

How silk is actually made

A silkworm moth lays several hundred eggs and dies shortly after. The larvae hatch and spend roughly a month eating almost constantly, growing to many times their birth weight before they begin spinning a cocoon. Spinning takes two to three days: the worm secretes a liquid protein that hardens into filament on contact with air, wrapping itself in a single continuous thread that can run over a thousand metres long.

Harvesting that filament is called reeling. Cocoons are simmered in hot water to loosen the sericin gum holding the filament together, then the thread is unwound and combined with others to form a usable yarn. That yarn is woven into fabric, finished, and only then does it become the smooth, lustrous material people picture when they hear "silk."

What silk is actually made of

Silk fibre is built from two proteins: fibroin, which forms the core filament and gives silk its strength, and sericin, the gum that coats and protects it during the worm's lifecycle and gets washed away during processing. The fibre's structure, long, smooth, and roughly triangular in cross-section, is what bends light into silk's characteristic sheen rather than a flat shine, and what lets fabric made from it slide against skin and hair rather than catch.

The real types of silk

Mulberry silk, from the farmed Bombyx mori silkworm feeding exclusively on mulberry leaves, accounts for the large majority of silk produced worldwide and is what most bedding and sleepwear is built from. Alongside it are several wild and semi-wild silks, each from a different species: tussah, muga, and eri, each with its own colour, texture and traditional use. See the full breakdown at mulberry silk vs other silk types.

"Raw silk" isn't a separate type at all. It's silk in its unrefined state, before degumming, true of any silk species including mulberry. More on that distinction at mulberry vs raw silk.

A brief history

Silk production is generally traced to Neolithic China, with legend crediting its discovery to a cocoon that fell into a cup of hot tea and unravelled into a single long thread. Whatever the exact origin, China kept the process a closely guarded secret for centuries before it spread along the trade routes that came to be called the Silk Road, eventually reaching India, the Middle East, and Europe.

What silk is actually used for

• Bedding and sleepwear. Silk's smooth fibre means less friction against skin and hair overnight than cotton, which is the whole case for a silk pillowcase or sleep mask.
• Fashion. Its drape and sheen have made it a fabric for formal wear for centuries.
• Biomedical research. Silk fibroin is an active area of study for wound dressings and tissue scaffolding, though that's a research application, not something in consumer products today.

Caring for silk

Cool hand wash with a pH-neutral, silk-specific detergent, then lay flat to dry away from direct heat or sun. No bleach, no fabric softener, no dryer. The full routine, including what to check on a detergent label, is at the best detergent for washing silk.

Silk alternatives

Rayon (viscose), often called artificial silk, is a semi-synthetic fibre made from processed wood cellulose. Polyester and nylon satin imitate silk's weave and shine without sharing the fibre. All three are cheaper than real silk and don't share its breathability or its momme-measurable weight. More on telling them apart at mulberry silk vs artificial silk.

Common questions

Is silk environmentally friendly?

It's biodegradable and doesn't shed microplastics the way synthetic fibres do, which are real advantages. Whether it's the single most sustainable fabric overall is a harder claim to stand behind, since farming any natural fibre at scale has a real water and land footprint.

Is silk more delicate than other fabrics?

It needs specific care, a cool wash and a gentle detergent, but it isn't as fragile as its reputation suggests. Handled properly, silk holds up for years.

Is silk better in summer or winter?

Its breathability suits warm weather especially well, but its temperature-regulating properties make it comfortable across seasons, not just summer.

Silk Pearl works exclusively in 22 momme mulberry silk, OEKO-TEX certified. See the full range in the shop.