Silk stands as one of the world's most coveted natural fibers, prized for its lustrous appearance, smooth texture, and remarkable strength. This ancient textile has adorned royalty and the wealthy for thousands of years, maintaining its status as a symbol of luxury in modern times. Dating back to ancient China around 3000 BCE, silk's production methods were once so closely guarded that revealing them was punishable by death.
The discovery of silk dates back to ancient China, approximately 5,000 years ago. According to Chinese legend, Empress Leizu (Xi Lingshi) discovered silk accidentally while drinking tea under a mulberry tree when a cocoon fell into her cup. As she removed it, the cocoon began to unravel, revealing a long, shimmering thread. Recognizing its potential, she cultivated silkworms and developed the first silk reel.
Archaeological evidence confirms silk production in China by at least 3000 BCE, with silk fabric remnants discovered in tombs from the Yangshao culture period. By 2000 BCE, silk had become a cornerstone of Chinese culture and economy, with established techniques for cultivation, processing, and weaving. The fiber's value was so significant that it served as currency and tribute payments.
For nearly 3,000 years, China maintained a global monopoly on silk production through strict secrecy. The Chinese government enacted laws making the unauthorized export of silkworms or their eggs a capital offense. This exclusivity created the legendary Silk Road, a network of trade routes connecting East Asia to the Mediterranean world, named for the valuable fiber that justified the dangerous journey.
Silk's introduction to other civilizations occurred gradually. Korea received silkworm eggs and production methods around 200 BCE. By the first century CE, the closely guarded secret reached Japan through Chinese immigrants and Buddhist monks. India developed its own silk varieties and techniques, focusing on wild silks like tussar that didn't require the intensive cultivation methods of mulberry silk.
The Byzantine Empire broke China's monopoly around 550 CE when Emperor Justinian I reportedly smuggled silkworm eggs from China inside hollow walking sticks carried by Nestorian monks. This introduction established the Byzantine silk industry, centered in Constantinople, creating significant economic and political repercussions by reducing dependence on Chinese imports.
Silk production spread throughout the Muslim world during the medieval period. The Islamic conquest of Persia and parts of the Byzantine Empire transferred silk-making knowledge to Damascus, Baghdad, and Al-Andalus (Spain). These regions developed distinctive silk weaving styles, with Persian and Arab weavers introducing innovative patterns and techniques that influenced European textiles.
The Italian city-states, particularly Lucca, Venice, Florence, and Genoa, established Europe's first significant silk industries beginning in the 12th century. These production centers incorporated Byzantine and Islamic influences while developing distinctive Italian styles. By the Renaissance, Italian silk had achieved a reputation for exceptional quality that rivaled even Chinese production.
France developed a major silk industry centered in Lyon beginning in the 15th century, actively supported by the French monarchy. King Louis XI established Lyon as the center of the French silk trade in 1466. Under Louis XIV, minister Jean-Baptiste Colbert implemented policies to make French silk the finest in Europe, securing royal patronage that elevated French silk to international prominence.
The Industrial Revolution transformed silk production in the 19th century. The invention of the Jacquard loom in 1804 by Joseph Marie Jacquard revolutionized pattern weaving using punch cards to control individual warp threads—a system that later influenced early computer development. Mechanization increased production capacity while reducing costs, though many premium silk products continued to rely on traditional handcrafting techniques.
Disease significantly disrupted European silk production in the 1850s when pébrine disease decimated silkworm populations. Louis Pasteur's research into the epidemic laid groundwork for modern microbiology while saving the French silk industry. The crisis accelerated Japan's emergence as a major silk producer, as they could provide disease-free silkworm eggs to European producers.
The 20th century brought significant challenges to traditional silk producers with the development of synthetic fibers. Rayon (initially marketed as "artificial silk") appeared in the 1890s, followed by nylon in the 1930s, which was explicitly developed to replace silk stockings. During World War II, silk supplies to Western countries were cut off when Japan (then the world's largest silk exporter) entered the conflict, accelerating the adoption of synthetic alternatives.
Modern silk production has shifted dramatically since 1980. China has reemerged as the dominant global producer, accounting for approximately 80% of world output. India maintains the second position, with significant production in Brazil, Uzbekistan, Thailand, and Vietnam. Contemporary production combines traditional methods with technological innovations to maintain competitiveness with synthetic alternatives while addressing sustainability and ethical concerns.
Today's silk industry faces both challenges and opportunities. Ethical concerns about conventional harvesting methods have spurred growth in peace silk production. Environmental considerations drive development of more sustainable processing techniques. Meanwhile, advanced research explores applications beyond traditional textiles, including medical implants, optical materials, and technical composites, ensuring this ancient fiber maintains relevance in contemporary applications.
Silk is a filament, not a staple fibre, and that single fact explains most of what follows. A Bombyx mori larva spins its cocoon as one continuous strand, and a single cocoon yields somewhere between 600 and 900 metres of usable filament. Cotton and wool have to be spun from short lengths; silk does not, which is why its surface is smooth enough to reflect light in a line rather than scatter it.
That continuous filament is also what silk grades measure. The long, unbroken filament reeled from an intact cocoon becomes the highest grade — what is sold as 6A mulberry. Broken or short lengths are carded and spun instead, producing dupioni, noil and the cheaper spun silks, which is why two fabrics both called silk can feel nothing alike.
Wild silks are the exception. Tussar, eri and muga come from moths that are not domesticated, and their cocoons are opened rather than reeled whole, so those fabrics carry a coarser hand and an uneven colour that domesticated mulberry silk does not. For a buyer, the practical marker is simple: ask whether the yarn is reeled or spun before asking about the weave.
Silk possesses a remarkable combination of physical and sensory properties that have maintained its status as a premium fiber throughout human history. Understanding these properties helps explain silk's enduring appeal despite its relatively high cost.
Tensile strength stands among silk's most impressive physical characteristics. Gram for gram, silk fiber rivals steel in tensile strength while maintaining extraordinary flexibility. This unique combination provides durability while allowing the fluid draping qualities prized in fashion applications.
Temperature regulation represents one of silk's most practical benefits. The fiber structure naturally wicks moisture away from the body while providing excellent insulation properties. This creates the seemingly contradictory effect of keeping wearers cool in summer and warm in winter, making silk garments particularly valuable in variable climates.
Light interaction creates silk's characteristic luster through a phenomenon called triangular prism effect. The triangular structure of silk fibers reflects light at different angles, creating the subtle glow that distinguishes fine silk from synthetic alternatives. This natural iridescence changes subtly with movement, creating the distinctive visual depth associated with premium silk fabrics.
Moisture absorption capabilities further enhance silk's comfort characteristics. The fiber can absorb up to 30% of its weight in moisture without feeling damp to the touch. This hygroscopic quality helps regulate humidity next to the skin, contributing to silk's reputation for comfort in various environmental conditions.
Hypoallergenic properties make silk particularly valuable for sensitive individuals. The smooth fiber surface resists dust accumulation, while the protein structure—similar to human hair—rarely triggers allergic reactions. For those with sensitive skin or respiratory concerns, silk bedding and clothing often provide relief from symptoms triggered by other fibers.
Sound absorption represents a lesser-known but valuable property. Silk fabrics effectively dampen sound waves, making them excellent choices for acoustic applications ranging from theater curtains to home furnishings where noise reduction matters. This characteristic stems from the irregular molecular structure that disrupts sound wave propagation.
UV resistance provides natural protection against solar radiation. While not comparable to modern technical fabrics, silk historically offered better sun protection than other natural fibers, contributing to its popularity in traditional hot-climate garments. Modern testing confirms silk blocks approximately 97% of UV radiation when woven in appropriate structures.
Electrical resistance characteristics make silk a natural electrical insulator. This property made silk thread historically valuable for early electrical applications before synthetic alternatives became available. Even today, some specialized electrical applications utilize silk components where its combination of insulation and biodegradability proves advantageous.
Exceptional comfort represents perhaps silk's most immediate advantage to wearers. The smooth fiber surface glides gently against skin without causing irritation, while its temperature-regulating properties maintain comfortable body temperature in various conditions. These properties make silk particularly valuable for intimate garments and bedding.
Durability despite delicate appearance gives silk significant longevity when properly maintained. Silk garments with appropriate care can last for generations, often outlasting synthetic alternatives despite their seemingly more robust construction. This longevity offsets the higher initial investment over time.
Natural biodegradability addresses growing environmental concerns about synthetic textiles. Pure silk decomposes completely within 1-5 years in standard composting conditions, unlike petroleum-based synthetics that persist for decades or centuries. This biodegradability extends to production waste, reducing environmental impact throughout the lifecycle.
Health benefits arise from silk's hypoallergenic and antimicrobial properties. The smooth fiber surface discourages dust mite accumulation, beneficial for allergy sufferers, while the natural protein structure inhibits bacterial and fungal growth. These properties make silk particularly valuable for those with sensitive skin conditions like eczema or rosacea.
Versatility across applications demonstrates silk's exceptional adaptability. Few other materials transition so effectively from delicate lingerie to structured outerwear, from lightweight summer garments to warm winter accessories. This versatility makes silk investment pieces particularly valuable within versatile wardrobes.
High cost represents silk's most obvious disadvantage for many consumers. The labor-intensive production process, biological limitations on supply, and specialized processing requirements all contribute to price points significantly higher than synthetic alternatives or even other natural fibers like cotton.
Cleaning challenges create maintenance difficulties for many owners. While some silk items can be hand-washed, others require professional dry cleaning, adding ongoing care costs. Water spots, perspiration damage, and susceptibility to certain staining agents further complicate maintenance.
Ethical concerns about conventional harvesting methods trouble many consumers. The standard practice of killing silkworms before they emerge from cocoons raises animal welfare questions. While peace silk alternatives address these concerns, they typically cost more and offer slightly different characteristics than conventional silk.
Environmental impacts from conventional production include intensive water usage during processing and chemical treatments during dyeing. While silk itself biodegrades readily, certain processing chemicals used in conventional production can create environmental concerns that consumers must weigh against advantages.
Durability concerns in specific conditions create practical limitations. Silk's vulnerability to prolonged sunlight exposure causes yellowing and fiber weakening over time. Similarly, exposure to body oils and perspiration acids can gradually degrade silk fibers without proper cleaning, limiting silk's practicality for certain applications despite its general durability.
Mulberry silk represents the most common and highest quality silk variety globally. Produced from domesticated Bombyx mori silkworms fed exclusively on mulberry leaves, it accounts for nearly 90% of the world's silk production. This silk type features exceptionally smooth, strong, uniform fibers with the classic lustrous appearance most associated with fine silk.
Tussar silk (sometimes spelled tussah) comes from wild silkworms of the Antheraea genus that feed on oak and juniper leaves. Primarily produced in India, China, and Japan, this wild silk has a rich, deep gold color and more textured feel than mulberry silk. Its natural color ranges from golden-tan to deep brown, making it distinctive even before dyeing.
Eri silk has gained popularity as "peace silk" or "non-violent silk" because it's harvested after the moth has emerged from the cocoon naturally. Produced mainly in northeast India, this silk has a matte appearance and wool-like texture. While less shiny than mulberry silk, it offers excellent insulation properties and is often blended with other fibers.
Muga silk, exclusive to the Assam region of India, holds the distinction of being the world's most expensive commercial silk. Its natural golden color becomes more intense with washing and exposure to sunlight rather than fading. Historically reserved for royalty, muga silk remains rare due to its limited production region and the specific environmental conditions required.
Spider silk, though not commercially viable at scale, represents perhaps the most extraordinary silk variety. Research continues into ways to produce this remarkable fiber, which offers tensile strength comparable to high-grade steel while maintaining extraordinary elasticity. Some limited production has occurred through transgenic methods or by extracting silk directly from spiders, though mass production remains elusive.
Silk's versatility extends far beyond its traditional association with luxury fashion, encompassing applications from practical everyday items to cutting-edge technical uses. The fiber's unique properties make it suitable for an extraordinarily diverse range of products across multiple industries.
Fashion applications remain silk's most visible use, with high-end apparel leveraging both its aesthetic qualities and comfort properties. Designer evening wear frequently features silk charmeuse or chiffon, while business attire incorporates silk blends for their wrinkle resistance and professional appearance. Contemporary designers increasingly explore sustainable silk options like peace silk to address ethical concerns while maintaining luxury appeal.
Accessories represent another significant fashion category, with silk scarves, ties, and pocket squares maintaining their status as classic luxury items. These smaller pieces often showcase intricate printing or weaving techniques, displaying silk's exceptional color absorption and detail retention properties. Luxury brands frequently utilize silk accessories as entry-level products for aspirational consumers seeking association with premium labels.
Home textiles leverage silk's comfort and aesthetic properties across various applications. Silk bedding commands premium prices for its temperature regulation and skin-friendly surface that helps prevent wrinkles and reduce hair breakage. Decorative pillows, draperies, and wall hangings utilize silk's exceptional light interaction characteristics to create visual depth in interior design applications.
Silk also has uses outside textiles — surgical sutures are the oldest, and researchers work with silk proteins in wound dressings and drug delivery — but those draw on the protein rather than the cloth, and none of them affect what to look for when buying silk fabric.
Silk fabric characteristics vary widely depending on the weaving technique employed, creating a diverse range of textures and appearances from the same basic thread. Understanding these different weaves helps explain the substantial price differences between various silk fabrics.
Charmeuse weaving creates a fabric with a satin weave structure, resulting in a glossy front and matte back. This classic silk fabric drapes beautifully and has become synonymous with luxury lingerie and evening wear. Its smooth surface reflects light magnificently but makes any sewing imperfections highly visible.
Silk chiffon employs a plain weave technique using highly twisted yarns, creating a light, sheer fabric with a slightly crinkled surface. Despite its delicate appearance, silk chiffon offers surprising durability. Its floating, ethereal quality makes it a favorite for overlays, scarves, and evening wear.
Crepe de Chine features a plain weave using twisted yarns in the weft direction. This technique creates a lightweight fabric with a slightly crinkled or pebbly texture. The subtle texture helps hide wrinkles, making it practical for travel garments while maintaining an elegant appearance.
Dupioni silk comes from cocoons formed when two silkworms spin together, creating a textured fabric with characteristic slubs and irregular threads. These natural imperfections were once considered flaws but are now prized for their unique character. Dupioni has a stiffer hand than many other silk fabrics, making it excellent for structured garments and home décor.
Silk organza employs a plain weave with highly twisted yarns, creating a thin, crisp, and transparent fabric with significant body. Its stiff feel makes it ideal for structural elements in fashion and has become particularly popular for wedding gowns and formal wear overlays.
Silk satin represents one of the most recognizable luxury fabrics, characterized by its smooth, glossy surface achieved through a satin weave structure. This weaving technique allows more of the warp threads to float over filling threads, creating more light reflection and the characteristic sheen.
Silk remains among the most expensive natural fibers on the market for several interconnected reasons. The intensive labor requirements stand as the primary factor driving costs. Throughout the production chain, from raising silkworms to the final weaving process, skilled human attention remains essential despite some mechanization efforts.
The biological realities of silk production impose natural limitations on supply. It takes approximately 2,500-3,000 silkworms consuming 104 pounds of mulberry leaves to produce just one pound of raw silk. This biological inefficiency creates an inherent scarcity reflected in market pricing.
Quality variations significantly impact pricing structures. Silk grades consider factors like color consistency, cleanliness of the thread, diameter uniformity, and tensile strength. The highest grades feature perfect color uniformity with minimal slubs or irregularities, commanding premium prices in the marketplace.
Geographic production regions dramatically influence cost structures. China leads global production, accounting for approximately 80% of the world's silk, followed by India, Uzbekistan, and Brazil. Labor costs, environmental regulations, and infrastructure differences across these regions create price variations for seemingly similar products.
Weaving techniques contribute substantially to finished fabric pricing. Simple weaves like plain silk require less time and expertise compared to complex patterns like jacquards or hand-embroidered pieces. The most expensive silk fabrics often combine premium raw materials with intricate, time-consuming weaving methods requiring specialized skills.
Current market prices span a remarkable range. Raw silk typically costs between $20-80 per yard, with Chinese silk generally less expensive than Indian or Italian varieties. Basic commercial silk fabrics range from $15-30 per yard for simple weaves, while designer silk fabrics often start at $100 per yard and can reach several hundred dollars for hand-woven or specially treated varieties.
Finished silk garments demonstrate even greater price elasticity. Simple silk scarves might retail for $50-100, while premium designer silk dresses often reach $1,000-5,000. Haute couture silk creations, particularly those with hand embellishments or historical significance, regularly command prices exceeding $10,000, reflecting both material costs and artistic value.
The silk industry employs numerous certifications and standards that help manufacturers, retailers, and consumers verify quality, sustainability, and ethical practices. These certifications have become increasingly important as conscious consumers seek transparency about the products they purchase.
OEKO-TEX Standard 100 represents one of the most widely recognized textile certifications globally. This certification specifically tests for harmful substances in textiles, ensuring silk products are safe for human contact. The standard includes testing for banned azo dyes, formaldehyde, pesticides, and heavy metals often found in processing chemicals. OEKO-TEX certification applies to the item itself, whether fibre, yarn, fabric or finished product, rather than to the conditions under which it was produced, which is what STeP and MADE IN GREEN cover.
Global Organic Textile Standard (GOTS) provides comprehensive oversight of organic status throughout the textile supply chain. For silk, GOTS certification verifies that mulberry trees used for silkworm feeding were grown without synthetic pesticides or fertilizers. The certification also covers processing standards, prohibiting harmful chemicals during degumming and dyeing while enforcing wastewater treatment requirements. GOTS additionally includes social criteria, ensuring fair labor practices throughout production.
Intertek's silk certification services focus primarily on quality assurance and technical performance verification. Their testing evaluates physical properties like tensile strength, color fastness, abrasion resistance, and fabric weight consistency. Intertek also offers chemical testing that identifies restricted substances and verifies fiber composition claims. For luxury silk marketers, Intertek's authentication services help combat counterfeit products by verifying genuine silk against synthetic alternatives through specialized burn tests and microscopic analysis.
SGS provides comprehensive silk testing across multiple parameters including safety, quality, and performance. Their specialized silk testing protocols evaluate products against both regulatory requirements and voluntary standards. SGS certification often includes evaluation of colorfastness to washing, perspiration, and light exposure—critical concerns for silk products. Their Eco Testing division specifically examines environmental claims, verifying "organic silk" designations through fiber analysis and chemical residue testing.
Fair Trade certification, while less common in silk than in commodities like coffee or cotton, has gained traction in recent years. This certification focuses on ensuring equitable compensation for silk farmers and workers throughout the production chain. Fair Trade silk typically commands a 15-30% price premium, with proceeds directed toward community development projects in producing regions. The certification's traceability requirements create transparent supply chains that allow consumers to connect with the source of their silk products.
Bluesign certification addresses comprehensive environmental management throughout the textile production process. For silk producers, Bluesign certification requires elimination of particularly harmful chemicals used in processing while emphasizing resource efficiency. The system particularly focuses on reducing water consumption during the water-intensive degumming process and improving energy efficiency in temperature-controlled silkworm rearing facilities.
Cradle to Cradle certification evaluates products across five quality categories: material health, material reutilization, renewable energy use, water stewardship, and social fairness. Silk products achieving this certification demonstrate exceptional environmental performance throughout their lifecycle. The biodegradability of pure silk gives it advantages in achieving higher certification levels compared to synthetic alternatives, though chemical treatments during processing can sometimes affect this natural biodegradability.
Responsible Wool Standard (RWS), though primarily developed for wool, has expanded its methodology to create the Responsible Silk Standard. This emerging certification specifically addresses animal welfare concerns in sericulture, establishing standards for silkworm raising conditions, handling procedures, and euthanasia methods when applicable. The standard aims to improve practices industry-wide while providing transparency for consumers concerned about ethical silk production.
ISO 9001 certification, while not specific to silk, verifies quality management systems throughout production. Silk manufacturers with this certification demonstrate consistent quality control measures, traceability protocols, and continuous improvement processes. For luxury silk producers, this certification helps maintain the exceptional quality standards necessary in premium markets.
EU Ecolabel certification evaluates environmental impact across the entire lifecycle of textile products, including silk items. The certification restricts harmful substances while promoting production processes that minimize air and water pollution. For silk specifically, the certification examines energy consumption during processing and places restrictions on certain dyeing and finishing treatments that pose environmental concerns.
Proper silk maintenance significantly impacts its longevity and appearance, justifying the investment in this premium material. Despite its delicate reputation, silk proves remarkably durable when cared for appropriately, with some garments remaining beautiful for generations.
Cleaning represents the most critical aspect of silk care. While many silk items recommend dry cleaning, gentle hand washing often provides excellent results for less structured pieces. Cold water with neutral pH specialty detergents designed for protein fibers works best, as alkaline cleaners can damage the fiber structure.
Stain treatment requires prompt, gentle attention. Water-based stains often respond well to quick blotting with absorbent cloth, while oil-based stains may require professional attention. Common household stain removers frequently contain enzymes or bleaching agents that can permanently damage silk fibers.
Drying techniques significantly impact silk's appearance and longevity. Air drying away from direct sunlight prevents yellowing and fiber weakening. Hanging wet silk garments can distort their shape due to water weight, making flat drying on clean towels preferable for most items.
Storage considerations help preserve silk's beauty between wearings. Acid-free tissue paper prevents creasing during storage, while breathable garment bags protect against dust without trapping humidity that could promote mildew growth. Cedar blocks provide natural moth protection without the chemical residue of mothballs.
Ironing, when necessary, should occur while the silk remains slightly damp, using the lowest effective heat setting and a pressing cloth to prevent direct iron contact. Many silk varieties benefit from steam rather than direct ironing, allowing wrinkles to relax without mechanical pressure.
Silk is made primarily of protein fibers produced by certain insect larvae to form their cocoons. The most common commercial silk comes from the Bombyx mori silkworm, though other insects like spiders, bees, and various moth species also produce silk fibers. The silkworm produces two proteins—fibroin (the core structural component) and sericin (the sticky outer coating)—which combine to form the silk thread. During processing, the sericin is typically removed through degumming, leaving the fibroin fibers that become the commercial silk used in textiles. These protein fibers consist of amino acid chains arranged in a specific crystalline structure that gives silk its characteristic strength and luster.
100% silk refers to fabric composed entirely of silk fibers without any synthetic or other natural fiber blends. It specifically contains only the fibroin protein fibers extracted from silkworm cocoons after the sericin coating has been removed through degumming. True 100% silk contains no additives, fillers, or other fibers like polyester, cotton, or rayon that might otherwise be blended to reduce costs or alter properties. However, 100% silk may still contain dyes, finishes, or treatments applied during manufacturing to enhance color, texture, or performance characteristics. These treatments do not change its classification as 100% silk as long as the fiber content remains purely silk. High-quality 100% silk typically specifies the variety used, such as "100% Mulberry Silk," indicating silk derived exclusively from Bombyx mori silkworms fed on mulberry leaves.
Silk is a natural protein fiber produced by certain insect larvae, most commonly the Bombyx mori silkworm, to form protective cocoons. Its value derives from a unique combination of physical properties, production limitations, and historical significance. Physically, silk offers an unmatched combination of strength, luster, smooth texture, lightweight construction, and comfort. Its protein structure creates exceptional tensile strength while maintaining flexibility, and its triangular fiber structure refracts light to create its characteristic sheen. Production limitations significantly restrict supply—it requires approximately 2,500-3,000 silkworms to produce one pound of raw silk, with each silkworm fed exclusively on mulberry leaves and requiring careful environmental control. Historically, silk's limited production regions and closely guarded production techniques made it extraordinarily rare, leading to its association with royalty and wealth. The labor-intensive harvesting and processing procedures further increase value, as many steps resist mechanization and require skilled craftsmanship. Together, these factors maintain silk's status as a premium textile despite technological advances that have made many other historical luxury materials more accessible.
Silk is classified as a natural protein fiber fabric derived from animal sources, specifically the secretions of certain insect larvae. Unlike plant-based natural fibers like cotton or linen that consist primarily of cellulose, silk belongs to the protein fiber category alongside wool, cashmere, and angora. Its specific protein composition—primarily fibroin—creates distinctive properties that differentiate it from other protein fibers. Silk typically creates lightweight, smooth fabrics with exceptional drape characteristics. The specific weaving technique employed dramatically influences the resulting fabric type, creating variations from sheer chiffon to structured dupioni while maintaining silk's characteristic properties. As a fabric category, silk stands apart from both synthetic petroleum-based fabrics like polyester or nylon and cellulose-based natural fabrics in its performance characteristics, notably its superior moisture management, temperature regulation, and natural luster. While silk can be blended with other fibers to create hybrid fabrics with modified characteristics, pure silk remains distinctive and immediately recognizable to experienced textile handlers.
Hold it. Silk warms to your hand within seconds; polyester stays cool. Crush a corner and let go — silk creases softly and the crease falls out, polyester springs back with almost none. The reliable test is a burn test on a loose thread: silk smells of burnt hair and crumbles to ash, polyester melts into a hard bead.
Momme is silk's weight unit, roughly the pounds a 45-inch by 100-yard piece would weigh. Higher momme means denser cloth, not better silk: 12 to 16 momme suits scarves that need to knot, 19 to 22 suits pillowcases and sleepwear. A listing that gives no momme is usually not silk.
Some silk is, on a cold delicate cycle in a mesh bag with a pH-neutral detergent, but hand washing under 30°C is what preserves the surface. The damage from machine washing is cumulative rather than immediate — agitation abrades the filament and the sheen dulls over repeated cycles rather than in one wash.