Silk is a natural fiber known for its smooth texture and beautiful luster. It comes from the cocoons of silkworms, primarily the Bombyx mori moth. For thousands of years, silk has been treasured for its strength, softness, and elegance, making it one of the most luxurious fabrics in the world.
Not all silk is created equal. The grade of silk determines its quality, durability, and price. Understanding these grades helps you make informed choices when purchasing silk products, whether it's clothing, bedding, or decorative items.
The scale runs from 6A at the top to F at the bottom, with plain A between 2A and B. The rating sets the end use: 6A for high-end bedding, A for luxury garments, B for everyday pieces, C and below for blends.
In the silk industry, particularly following China's GBT 1797-2008 Raw Silk Quality Standards, silk is graded on a comprehensive scale ranging from 6A at the highest end, through 5A, 4A, 3A, 2A, A, B, C, D, E, to F at the lowest end. The 6A designation represents the absolute pinnacle of silk quality, accounting for only about 5-10% of total silk production. This elite grading is determined through rigorous testing of multiple factors including fiber length, size deviation, evenness, cleanness, neatness, tenacity, and minimal defects.
It's important to understand that these grades apply specifically to raw silk before processing into finished products. The 6A grade designation indicates that the raw silk meets the most stringent quality standards across all test criteria. Once silk is processed into finished products like clothing or bedding, these original raw silk grades are no longer directly visible or testable by consumers.
6A grade raw silk is characterized by exceptionally long, uniform fibers with virtually no imperfections. It has a distinctive pearly white natural color without impurities and possesses an extraordinary luminous sheen that cannot be replicated in lower grades. The fibers are remarkably strong yet incredibly smooth, providing unparalleled softness against the skin. Due to its superior quality, 6A silk is typically reserved for luxury brands and high-end products where the ultimate in silk quality is demanded.
Grade A silk (without a numerical prefix) represents high-quality raw silk but is a step below the premium 6A grade. It features long, continuous fibers with minimal imperfections or broken threads. The texture is smooth and even, with a good natural sheen. This quality silk feels substantial to the touch and drapes elegantly. It offers excellent durability, often lasting for many years with proper care. Grade A silk is commonly used in quality fashion garments, good bedding sets, and fine accessories where quality matters but the extreme refinement of 6A isn't required.
Grade B silk represents the middle-tier option in raw silk quality. The fibers are shorter than those found in Grade A silk, with some minor imperfections visible upon close inspection. The texture remains pleasant but less uniform than premium silk, and while it still has a lovely shine, it's not quite as brilliant as Grade A. Grade B silk contains more clumps which can create unevenness and air pockets in products like comforters. It offers reasonable durability and comfort at a more accessible price point. This makes it popular for everyday silk garments, affordable home textiles, and situations where the natural benefits of silk are still desired but at a lower cost.
Grade C silk is the lowest commercial grade commonly available. It's often made from the innermost layer of silk closest to the cocoon after higher grades have been harvested. It's characterized by shorter fibers and more visible imperfections throughout the fabric. The texture tends to be rougher compared to higher grades, and the appearance is noticeably duller with less of the luminous quality silk is famous for. This grade of silk typically feels thinner and less smooth against the skin. Its lower durability means it may not withstand repeated wear and washing as well as better grades. Grade C silk is typically used for less expensive products or blended with other fibers to create more affordable silk-blend fabrics.
Mulberry silk is widely considered the finest variety of silk available today. It's produced by silkworms that feed exclusively on mulberry leaves, resulting in extremely smooth, fine fibers that create an exceptionally soft fabric. This silk is naturally white, making it ideal for dyeing to create vibrant colors. It's prized for its hypoallergenic properties, making it suitable for those with sensitive skin. The long, strong fibers of mulberry silk create a luxurious fabric that's both durable and comfortable. Grade 6A mulberry silk joins two separate labels: mulberry names what the worm ate, 6A names how the reeled thread tested. Mulberry silk grades run the whole scale, so the word mulberry alone tells you nothing about grade.
Wild silk, also known as Tussah silk, comes from silkworms that aren't cultivated in controlled farm environments. These silkworms feed on oak and juniper leaves in the wild, producing silk with distinctive characteristics. Wild silk contains shorter, coarser fibers than cultivated varieties, giving it a more textured feel that some people prefer. It typically has a natural tan or golden color that cannot be completely removed even with bleaching, lending it a rustic, organic appearance. Despite its less refined nature, wild silk often offers greater durability in some applications. This unique silk creates fabrics with character and is especially popular for home décor items and casual garments where its natural variations are considered part of its charm.
Charmeuse refers not to a grade or source of silk but to a particular weaving technique that creates a distinctive fabric. This weaving method produces silk with a satin-like shiny front surface and a matte back side. The result is a fabric with fluid drape and a soft, sensuous feel that makes it perfect for lingerie, evening wear, and luxurious linings. Charmeuse can be created using various grades of silk, though Grade A produces the most spectacular results with the highest sheen and smoothest finish. The way light plays across charmeuse silk creates a subtle, shifting appearance that's been prized by fashion designers for generations. This versatile weave brings out silk's natural beauty while enhancing its draping qualities.
| Characteristic | Grade 6A Silk | Grade A Silk | Grade B Silk | Grade C Silk |
|---|---|---|---|---|
| Market Availability | Only 5-10% of total silk production | Limited but more available than 6A | Widely available | Very common |
| Fiber Length | Exceptionally long, continuous fibers | Long, continuous fibers | Moderately long fibers | Shorter fibers |
| Imperfections | Virtually none | Minimal | Some minor imperfections | More visible flaws |
| Texture | Supremely smooth and perfectly even | Very smooth and even | Good but less uniform | Rougher, less refined |
| Appearance | Exceptional pearly white with extraordinary luminous sheen | Rich, luminous sheen | Good luster | Duller finish |
| Durability | Superior, heirloom quality | Excellent, long-lasting | Good | Fair to moderate |
| Price Range | Highest premium | Premium | Moderate | Budget-friendly |
| Common Uses | Ultra-luxury apparel, high-end bedding, exclusive accessories | Luxury apparel, fine bedding | Everyday silk garments, home textiles | Affordable products, blended fabrics |
It's important to understand that silk grades (6A, 5A, 4A, etc.) technically apply only to raw silk before it's processed into finished products. When shopping for silk items like clothing, bedding, or accessories, these official grades aren't directly visible or verifiable in the final product. The best quality silk you can buy is top-grade mulberry, recognized by these five checks:
The most reliable indicator of silk quality in finished products is its texture and feel. High-quality silk feels exceptionally smooth and soft to the touch, with a natural coolness that gradually warms to body temperature. The surface should feel even and consistent throughout, without rough patches or irregularities. Premium silk drapes beautifully and has a subtle weight that feels luxurious without being heavy.
Quality silk has a natural, subtle luster that creates a gentle glow rather than a harsh shine. When examined in good lighting, premium silk displays a beautiful interplay with light, with the color appearing to have depth. The sheen should be consistent across the entire fabric. Look for evenness in the weave and color with no visible slubs, knots, or irregular threading unless they're intentional design elements.
High-quality silk is naturally breathable and temperature-regulating. It should feel cool in warm weather and provide comfortable warmth in cooler conditions. Quality silk also has natural elasticity - gently stretch the fabric and it should return to its original shape without distortion. When draped, it should fall in elegant, fluid folds rather than stiffly or unnaturally.
Colorfastness measures how well the dye stays put when silk is washed, rubbed or sweated on, and it is the one quality here a supplier can put a number on. That number is a 1 to 5 grade read off a standard grey scale, where 5 means no visible change and 4-5 is a defined half step.
Ask which test produced it: ISO 105-C06 for washing, ISO 105-X12 for rubbing, ISO 105-E04 for perspiration. Buyers usually write grade 4 for color change on the wash test, and 4-5 for printed bedding.
Light is the exception: ISO 105-B02 rates fading against blue wool numbered 1 to 8, and AATCC 16 reports in its own fading units. A bare grade 4 means nothing until the test is named.
An OEKO-TEX Standard 100 certificate covers only part of this. Its product class II, the class for scarves and pillowcases, requires staining grades of 4 for dry rubbing and 3-4 for perspiration, and sets no wash, light or wet-rubbing requirement at all.
Color moving in the first wash and fading in daylight sit outside what the OEKO-TEX label certifies, and these grades are floors, not the ceiling a well-dyed silk reaches.
While not a perfect indicator, price often correlates with quality in silk products. Extremely low-priced "silk" items may be blended with synthetic fibers or made from lower quality silk. Genuine high-quality silk, especially from the better grades of raw silk, requires significant investment in materials and craftsmanship, which is reflected in the final price.
Regardless of grade, silk lasts longest when it is hand washed cold in a mild detergent, dried flat out of direct sun, and pressed on the reverse at the lowest heat.
In addition to the grade of silk, another important measurement of silk quality is its "momme" weight. Momme (pronounced "moe-mee") is the unit used to measure the density and weight of silk fabric. One momme equals approximately 4.340 grams per square meter, or about 1 ounce per square yard at 8 momme.
The higher the momme count, the heavier and more durable the silk fabric will be. Typical momme ranges include:
Momme weight and silk grade measure different things and move independently. A finished piece is set by three things at once: the grade the raw thread tested at, the momme weight it was woven to, and where it was reeled and woven.
A 6A pillowcase at 22 momme, a 6A scarf at 8 momme and a Grade B pillowcase at 19 momme are all real, and none of them is the same purchase.
Understanding silk grades provides insight into how raw silk is classified before it's transformed into finished products. The 6A grade represents the pinnacle of raw silk quality with its exceptionally long, uniform fibers, superior luster, and extraordinary softness and durability. However, it's crucial to recognize that these grades apply only to raw silk, not finished products you purchase as a consumer.
When shopping for silk items, focus on the quality indicators you can directly observe: the smoothness and evenness of texture, the natural lustrous sheen, how the fabric drapes, and its overall feel against your skin. High-quality finished silk products should feel smooth and luxurious, with a subtle, natural shine that indicates premium materials were likely used in their production.
The momme weight measurement remains useful for finished products as it indicates the density and weight of the silk fabric, which affects its durability and appropriate uses. Reputable brands that specialize in silk products are more likely to source higher-grade raw materials, though price often reflects this quality difference.
With this knowledge, you can make more informed choices when purchasing silk items, focusing on the tangible qualities that make silk such a prized fabric rather than relying solely on grade designations that might be used in marketing but cannot be independently verified in finished products.
6A grade is considered the best grade of raw silk according to China's GBT 1797-2008 Raw Silk Quality Standards. It represents the highest quality silk with exceptionally long, uniform fibers, minimal defects, and superior luster. However, remember that these grades apply only to raw silk before processing, not to finished silk products you purchase as a consumer.
The four main types of silk are:
Mulberry silk is widely considered the best quality silk type. It offers the smoothest, softest texture, the most uniform appearance, and the highest durability. The silkworms that produce mulberry silk are carefully cultivated and fed exclusively on mulberry leaves, resulting in exceptionally fine, strong, hypoallergenic fibers. The majority of premium silk products, including luxury bedding and high-end garments, are made from mulberry silk.
The standard Chinese raw silk grading system officially ranges from 6A (highest) to F (lowest), with 6A being the highest recognized grade. Some manufacturers may market products as "7A" silk, but this is not part of the official GBT 1797-2008 Raw Silk Quality Standards. Claims of 7A should be viewed with skepticism as they likely represent marketing exaggeration rather than an officially recognized higher grade.
Grade A silk refers to high-quality raw silk that meets specific standards of fiber length, uniformity, cleanliness, and lack of defects, but is one step below the premium 6A grade. It features long, continuous fibers with minimal imperfections and good natural luster. In the Chinese grading system, Grade A (without a numerical prefix) is positioned between 2A and B grades. It provides excellent quality for luxury products without the premium cost of the highest grades.
While the complete Chinese grading system is more extensive, silk is often simplistically categorized into three main grades for consumer understanding:
This simplified A-B-C grading makes it easier for consumers to understand relative quality differences, though it simplifies the more detailed official grading system.
Yes, 6A grade silk is the highest quality raw silk available according to official standards. It's exceptional in every measurable aspect: fiber length, evenness, cleanness, neatness, and minimal defects. Products made from 6A grade raw silk are generally of superior quality, with excellent softness, durability, and natural luster. However, remember that as a consumer, you cannot directly verify the 6A grade in finished products. Focus instead on the tangible qualities like smoothness, drape, and luster.
The "6A" designation represents the highest level in China's silk grading system (GBT 1797-2008). The "A" indicates the quality category, while the "6" signifies the highest level within that category. 6A grade raw silk must pass rigorous testing for size deviation, evenness, cleanness, neatness, winding breaks, tenacity, elongation, and minimal defects. It represents only about 5-10% of total silk production and is reserved for luxury products where exceptional quality is essential.
No, not all mulberry silk is 6A grade. Mulberry silk refers to the type of silk (produced by silkworms fed exclusively on mulberry leaves), while 6A refers to a specific quality grade of raw silk. Mulberry silk can be found in all quality grades, from 6A down to lower grades. While mulberry silk is generally considered the best type of silk, its specific grade depends on how it performs across multiple quality testing criteria. Many silk products are made from mulberry silk of varying grades to meet different price points and quality needs.# Understanding Silk Grades: A Simple Guide